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Car Forum / Driving, Maintenance, Tuning / Maintenance and Repair / September 2007Part 2: Troubleshooting overheating prob
Afternoon ... Overview (95 Camaro Z28 automatic) * Car never had overheating probs - then, from one minute to the next, overheats. * Replaced thermostat (w/Stant SuperStat Heavy-Duty 180 degree) and radiator cap. * Replaced water pump (I deduced it went bad, replaced with genuine AC Delco unit) * Replaced water temperature sensor (one located on water pump). * "Water hose" flushed engine - hose in thermostat housing, water out lower-radiator hose * Water hose flushed radiator from filler neck to lower outlet * Water hose flushed radiator from lower outlet up out filler neck ("reverse flush") * "Water hose" reverse flushed engine - water hose in lower rad hose up out water pump. "Primed" engine with coolant (Dex-Cool) before installing thermostat. Installed thermostat and housing. Filled radiator with coolant and water (50/50). I did notice that the manual calls for 15 quarts, but I couldn't even get 2 gallons worth of coolant/water mix (8 quarts - almost half what's called for) in the engine and radiator (about a quart left in the container). So I start the car up, confident that replacing the water pump, thermostat, radiator cap, a flush, and new 50/50 coolant mix will put me back on the road. (I also bled the system at the bleeder valves). No go. As the car is warming up (within 5 minutes), the temperature gauge gets to where it normally rests, then continues to climb upwards to red. For a moment, the gauge does begin to drop slightly, and I figure it's going to continue to drop back to its normal resting point. But then it begins to rise towards red and I shut the engine off. The in-dash temperature gauge's lower mark is 160, upper mark (top of red) is 260 and three marks between (1/4 (185), 1/2 (210), and 3/4 (235) - i'm guessing). The red begins about 1/2 way between the 3/4 mark and the top mark. Historically, the gauge normally rests around the 1/4 mark (185). It now climbs to the 3/4 (235) before, which is just shy of the lower-red mark, before I shut the engine off. Any ideas what I can look for next? Original post from a few days ago: http://groups.google.com/group/rec.autos.tech/browse_thread/thread/e5edf1262d716 ff6/d00cc7d1c56c71e0#d00cc7d1c56c71e0 >Any ideas what I can look for next? Maybe the new thermostat isn't working either? Can you try it with no thermostat at all and see what happens? Not a permanent fix, just for diagnosing. The only other thing I can think of is a blown head gasket allowing hot gasses in to the water. Clogged radiator or other similar problems normally come on slowly not all at once like this. Steve B. > >Any ideas what I can look for next? > [quoted text clipped - 5 lines] > hot gasses in to the water. Clogged radiator or other similar > problems normally come on slowly not all at once like this. Hi Steve ... It has crossed my mind to pull the thermostat, but havent. But now, and based on your recommendation, I will do that. As a follow-up, I decided to take the car for a drive around the block. As I drive down the street (30-40 MPH), the gauge climbs and I decide to turn from A/C to Heater (blowing to floor) and turn the temperature to HOT. The engine temp gauge continues upwards, then drops a little, then climbs a little higher, then drops a tiny bit, then climbs upwards to red as I return home. I pull in the garage and the engine temp is just in the red, so I turn the car off. I can hear the water boiling under the hood (radiator). I open the hood and I see the water is pushing out of the radiator and into the overflow tank and out its top onto the floor. I never felt any hot air at my feet (barefooted) when I had the heater on hot. Is this a case of water not flowing through the heater core? Could this be a case where my original overheating condition caused a blown head gasket, and now the blown head gasket is leaking hot gases into the cooling system and causing an overheating condition? Should I get a dye to check for combustion gases in the cooling system? Do I check compression on each cylinder? I'm perplexed. > overflow tank and out its top onto the floor. I never felt any hot > air at my feet (barefooted) when I had the heater on hot. Is this a > case of water not flowing through the heater core? Whenever I've seen that, that means there's air in the heater lines and not coolant. I think you can diagnose a blown head gasket by reading the plugs, but I know changing the plugs on a 95 Camaro is just a teeny bit of work... Ray >> overflow tank and out its top onto the floor. I never felt any hot >> air at my feet (barefooted) when I had the heater on hot. Is this a [quoted text clipped - 7 lines] > >Ray I have a '95 Fleetwood with the same engine. Needed plugs and wires a while back. If I could find the GM design engineer that was responsible for that nightmare I would love to drive to their house and kick some butt. Steve B. [snip] > >I think you can diagnose a blown head gasket by reading the plugs, but I > >know changing the plugs on a 95 Camaro is just a teeny bit of work... [quoted text clipped - 5 lines] > responsible for that nightmare I would love to drive to their house > and kick some butt. Better yet, Steve, I wish I could invite the engineer over here to my house and have him/her change the plugs, the rotor and cap, the water pump, among other items. > I think you can diagnose a blown head gasket by reading the plugs, but I > know changing the plugs on a 95 Camaro is just a teeny bit of work... And even worse than changing the plugs - in order to get to the distributor cap/rotor, one has to remove the air pump, water pump, radiator fan assembly, and crankshaft pulley. I simply can't imagine what the friggin engineer was thinking ... or for that matter, the engineer and the project manager were thinking ?!??!?!? I can't believe the project manager approved that one, "oh yea, what a great idea - put the distributor on the front of the engine, under and behind the water pump and the crankshaft pulley". On Sep 16, 7:51 pm, james.r...@gmail.com wrote: > > I think you can diagnose a blown head gasket by reading the plugs, but I > > know changing the plugs on a 95 Camaro is just a teeny bit of work... [quoted text clipped - 8 lines] > great idea - put the distributor on the front of the engine, under and > behind the water pump and the crankshaft pulley". the way I used to check for combustion leaks into the cooling system was to remove the thermostat and water pump drive belt, leave the thermostat cover off, fill the system and start it up and watch for bubbles. That isn't going to work on this cam driven water pump although you will find out if the pump is working :) Other than an exhaust gas sniffer I can't think what you could use. [snip] > the way I used to check for combustion leaks into the cooling system > was to remove the thermostat and water pump drive belt, leave the > thermostat cover off, fill the system and start it up and watch for > bubbles. That isn't going to work on this cam driven water pump > although you will find out if the pump is working :) Other than an > exhaust gas sniffer I can't think what you could use. I wonder if any of these items would be helpful: http://www.uview.com/cool.html#550000 Maybe "Airlift" or " Combustion Leak Tester" - not sure how to use the Leak Tester - would be nice if they provided more detail on how to use the tool. In article <1190028577.146838.77090@g4g2000hsf.googlegroups.com>, > [snip] > > the way I used to check for combustion leaks into the cooling system [quoted text clipped - 10 lines] > Leak Tester - would be nice if they provided more detail on how to use > the tool. Well, the airlift will be helpful in re-filling the cooling system -after- you determine the cause of overheating. The combustion leak tester works pretty much like the inset picture on the above link... The unit is filled with the fluid that comes in the kit, the unit is placed on the radiator fill and then the squeeze bulb is used to draw any vapors that are in the radiator thru the fluid. If the fluid changes color, combustion gas is present in the cooling system. One needs to be careful when using this tool especially on a vehicle that is violently regurgitating coolant back as you have described yours to be doing. Experience has taught that these things don't work if the amount of coolant entering the combustion chamber is sufficient to snuff any combustion to begin with. (it happens) Before doing anything else, I'd fit a piece of clear vinyl hose of the correct size to which ever heater hose supplies coolant to the heater core, run the engine and see if in fact coolant is being pumped by the water pump. Sounds like it isn't... [snip] > Before doing anything else, I'd fit a piece of clear vinyl hose > of the correct size to which ever heater hose supplies coolant to > the heater core, run the engine and see if in fact coolant is > being pumped by the water pump. Sounds like it isn't... Excellent idea - I'll give it a go. Does this suggest that this is a system that *requires* coolant flow through the heater core as part of the cooling system loop? My understanding is that some systems have a valve to control flow to the heater and some must have a constant flow to include a trip through the heater core. >[snip] >> Before doing anything else, I'd fit a piece of clear vinyl hose [quoted text clipped - 9 lines] >heater and some must have a constant flow to include a trip through >the heater core. There is a small coolant hose coming off the throttle body and going to the coolant reservoir. Pull it off, aim it back in to the reservoir and have someone start the car. You should have a good flow of water going through that hose. I think there is always flow through the heater core but I could be wrong. If you put the clear hose on turn it to max heat high fan just to make sure that coolant should be flowing. Steve B. [SNIP] > There is a small coolant hose coming off the throttle body and going > to the coolant reservoir. Pull it off, aim it back in to the > reservoir and have someone start the car. You should have a good flow > of water going through that hose. Hi Steve! The hose I see coming off the throttle body goes to the neck of the radiator, so I assume you mean that one .. and do I remove it at the throttle body and route that end down into the overflow tank? Or do I *leave* it connected at the throttle body and remove it at the radiator and check for flow coming out of the throttle body? I still need to get to the HW store to get some clear hose to check flow. I started the car (few minutes ago) up and re-bled the cooling system. When I turn the heater on and temp to HOT, I still get no hot air to my feet (or up the windshield when in Defrost). Also, I will check the fan relays - when I crawl under the front and feel for air, the fans are blowing, but I never hear them kick into high speed when the temperature climbs. >Hi Steve! The hose I see coming off the throttle body goes to the >neck of the radiator, so I assume you mean that one .. and do I remove [quoted text clipped - 3 lines] >still need to get to the HW store to get some clear hose to check >flow. My LT1 is in a Fleetwood so I can't tell you exactly where your hoses go but the flow should be out of the throttle body and back to the cooling system so I would pull it loose at end not connected to the throttle body and see what you get. >I started the car (few minutes ago) up and re-bled the cooling system. >When I turn the heater on and temp to HOT, I still get no hot air to >my feet (or up the windshield when in Defrost). Did you have water spraying out when you bled the system? >Also, I will check the fan relays - when I crawl under the front and >feel for air, the fans are blowing, but I never hear them kick into >high speed when the temperature climbs. I don't think fans are your issue. These cars will idle all day long only cutting on the low speed fan every now and again to cool the water. Steve B. In article <1190042088.485632.308060@57g2000hsv.googlegroups.com>, > [snip] > > Before doing anything else, I'd fit a piece of clear vinyl hose [quoted text clipped - 9 lines] > heater and some must have a constant flow to include a trip through > the heater core. What Steve B said. On Sep 17, 1:51 pm, james.r...@gmail.com wrote: > > I think you can diagnose a blown head gasket by reading the plugs, but I > > know changing the plugs on a 95 Camaro is just a teeny bit of work... [quoted text clipped - 8 lines] > great idea - put the distributor on the front of the engine, under and > behind the water pump and the crankshaft pulley". Hey a quick way to eliminate a lot of possibilities is take off the top radiator hose and see if water's pouring out, that'll tell you the pump and thermostat are working, if you put a garden hose into the radiator to keep it topped up you can make sure it isn't a blockage there either. You can also sometimes check for bubbles in the cold radiator to identify a blown head gasket/cracked engine >> I think you can diagnose a blown head gasket by reading the plugs, but I >> know changing the plugs on a 95 Camaro is just a teeny bit of work... [quoted text clipped - 8 lines] > great idea - put the distributor on the front of the engine, under and > behind the water pump and the crankshaft pulley". At the time it was heralded as a great idea. I think the opti-spark was originally intended to be a lifetime piece that never needed servicing, and if they sealed it better or didn't put it under the water pump it may have never needed service. Ray >I can hear the water boiling under the hood (radiator). I open the >hood and I see the water is pushing out of the radiator and into the >overflow tank and out its top onto the floor. I never felt any hot >air at my feet (barefooted) when I had the heater on . Is this a >case of water not flowing through the heater core?hot I wonder if your water pump is turning. I know it's a gear drive but there is no reason that gear couldn't have broken. >Could this be a case where my original overheating condition caused a >blown head gasket, and now the blown head gasket is leaking hot gases [quoted text clipped - 3 lines] > >I'm perplexed. After you confirm that the water pump is actually turning and water really is moving through the system then my next step would be to check for exhaust gas in cooling system. I know the radiator shops have the stuff on the shelf to test for exhaust in the coolant. I don't know if you can get something at the parts store that does the same thing. Plugs are such a nightmare on that engine that I would rather have a root canal than check the plugs and compression. Steve B. >>I can hear the water boiling under the hood (radiator). I open the >>hood and I see the water is pushing out of the radiator and into the [quoted text clipped - 24 lines] > > Steve B. Cannot he apply pressure to the radiator and check for a leakdown--to determine if there is leakage between coolant system and combustion chambers? sam > > Cannot he apply pressure to the radiator and check for a leakdown--to > determine if there is leakage between coolant system and combustion > chambers? I was wondering why nobody had mentioned that yet.  SignatureTegger > > > > Cannot he apply pressure to the radiator and check for a leakdown--to > > determine if there is leakage between coolant system and combustion > > chambers? > > I was wondering why nobody had mentioned that yet. 1) Because combustion pressure = hundreds of PSI, radiator pressure = 15 PSI. 2) As already stated, the spark plugs are a royal pain to R & R. > In article <Xns99AF5396EED78teg...@207.14.116.130>, > [quoted text clipped - 8 lines] > > 2) As already stated, the spark plugs are a royal pain to R & R. I still think it would be worthwhile to try; don't need to pull the spark plugs just listen for hissing at intake and exhaust. May need to try at several different engine positions. nate aarcuda69062 <nonelson@sbcglobal.net> wrote in news:nonelson- 1C53CF.08145518092007@newsclstr03.news.prodigy.net: >> > >> > Cannot he apply pressure to the radiator and check for a leakdown--to [quoted text clipped - 5 lines] > 1) Because combustion pressure = hundreds of PSI, radiator > pressure = 15 PSI. Yes, but could you not find a leak from combustion chamber to cooling passage with 130# shop air? My car (at the time about 200K miles) was drinking coolant. Tech fed shop air into each of the 4 cylinders. #1 blew bubbles into the coolant with shop air. A visual inspection of head/block mating surfaces and head gasket failed to reveal the point of leakage, probably because I caught it very early. A new gasket solved the problem. > 2) As already stated, the spark plugs are a royal pain to R & R. Good point. That was mentioned earlier, but I had forgot. SignatureTegger > >> > Cannot he apply pressure to the radiator and check for a leakdown--to > >> > determine if there is leakage between coolant system and combustion [quoted text clipped - 7 lines] > Yes, but could you not find a leak from combustion chamber to cooling > passage with 130# shop air? He could, but the spark plugs are a royal pain to R & R, which means threading a compression adaptor into the spark plug hole is an even bigger pain. The block checker fluid or a gas analyzer would be my first choice to save skinned knuckles. > My car (at the time about 200K miles) was drinking coolant. Tech fed shop > air into each of the 4 cylinders. #1 blew bubbles into the coolant with > shop air. A visual inspection of head/block mating surfaces and head gasket > failed to reveal the point of leakage, probably because I caught it very > early. A new gasket solved the problem. Indeed, I've been using that technique for many years, works great when things are easy to get at. LT1 F bodies are nowhere near that though. > > 2) As already stated, the spark plugs are a royal pain to R & R. > > Good point. That was mentioned earlier, but I had forgot. > As a follow-up, I decided to take the car for a drive around the > block. As I drive down the street (30-40 MPH), the gauge climbs and I [quoted text clipped - 9 lines] > air at my feet (barefooted) when I had the heater on hot. Is this a > case of water not flowing through the heater core? If you never felt hot air, it almost sounds like your water isn't being circulated at all. That would argue for either a slug if air trapped in the system which the waterpump can't dislodge, OR your waterpump isn't pumping, OR your system is completely blocked somewhere. On Sep 16, 6:24 pm, james.r...@gmail.com wrote: > Afternoon ... > [quoted text clipped - 5 lines] > * Replaced water pump (I deduced it went bad, replaced with genuine AC > Delco unit) Double check the water pump rotation, the auto parts store may have given you the wrong one. If they did, it's spinning the wrong way. cc In article <1190120302.289178.293170@g4g2000hsf.googlegroups.com>, > On Sep 16, 6:24 pm, james.r...@gmail.com wrote: > > Afternoon ... [quoted text clipped - 9 lines] > Double check the water pump rotation, the auto parts store may have > given you the wrong one. That would be pretty hard to do in this application. The pumps he's getting could very well be built wrong, but there's no confusing the pump design itself. > In article > <1190120302.289178.293...@g4g2000hsf.googlegroups.com>, [quoted text clipped - 18 lines] > The pumps he's getting could very well be built wrong, but > there's no confusing the pump design itself. On a 350 GM engine this is very easy to do, the waterpumps look the same for reverse rotation and normal rotation. Usually this sort of problem shows up when someone with a GM 4.3 installs a 350 waterpump with the wrong rotation. But, it's easy to tell.....some have an arrow showing rotation...you can also remove the hose to the heatercore and start the engine. A shitload of water says pump rotation is okay....just a dribble.......then you may have the wrong waterpump. cc On Sep 18, 9:04 am, CarCrazy...@gmail.com wrote: > On a 350 GM engine this is very easy to do, the waterpumps look the > same for reverse rotation and normal rotation. Usually this sort of [quoted text clipped - 4 lines] > rotation is okay....just a dribble.......then you may have the wrong > waterpump. Okay, *THAT'S* interesting. I checked the AC Delco part number on the box and it coincides with what I found on some auto-parts websites. I also put them up side-by-side (old/new) and checked everything before walking out of the store. I've never seen any arrows showing on this unit. (AAMOF, I've got quite a few pictures of the old and new unit - I'll double check). On Sep 18, 10:52 am, james.r...@gmail.com wrote: > On Sep 18, 9:04 am, CarCrazy...@gmail.com wrote: > [quoted text clipped - 13 lines] > unit. (AAMOF, I've got quite a few pictures of the old and new unit - > I'll double check). The difference would be the impeller, on the backside of the waterpump. The impeller would face one way for normal the other way for reverse. Most, afaik, 4.3's are reverse rotation, I'm not sure how many, if any, 350's are reverse rotation. Like I said, this was always a problem with owner's of 4.3's, where so many of the 350 parts would fit because the 4.3 is a 350 minus 2 cylinders. Parts like rocker arms were cheaper for the 350 and bolt right to the 4.3. Many tried the 350 waterpump on the 4.3 only to have the same problem you are having. cc >>In article >><1190120302.289178.293...@g4g2000hsf.googlegroups.com>, [quoted text clipped - 31 lines] > > cc but this is an LT1, not a "classic" small block. There is no reverse rotation version. The water pump is totally different. http://www.9c1.com/technical/LT1_rebuild/ar99928.htm http://www.gmhightechperformance.com/tech/0506htp_lt1_high_mileage_reliable_buil d/install_pictures.html Ray > CarCrazy...@gmail.com wrote: > [quoted text clipped - 42 lines] > > - Show quoted text - ahh...I see. You're right, the waterpumps I was talking about were for belt driven. ...then were are back to 'Is the pump turning? cc > but this is an LT1, not a "classic" small block. > There is no reverse rotation version. [quoted text clipped - 5 lines] > > Ray Thank you Ray! (seems some here are a little slow on the up-take) > In article <mmSHi.195658$fJ5.27497@pd7urf1no>, > [quoted text clipped - 10 lines] > Thank you Ray! > (seems some here are a little slow on the up-take) oops, sorry. Seems my bifocals don't work when my nose is THAT high in the air........ cc In article <1190213176.294215.131130@n39g2000hsh.googlegroups.com>, > > Thank you Ray! > > (seems some here are a little slow on the up-take) > > oops, sorry. Seems my bifocals don't work when my nose is THAT high in > the air........ > cc I suggest asking your optometrist about a pair of computer glasses... > In article > <1190213176.294215.131...@n39g2000hsh.googlegroups.com>, [quoted text clipped - 9 lines] > I suggest asking your optometrist about a pair of computer > glasses... .....I tried those once, they were a little bulky and windows kept crashing.... a real pane. (-E: -= .....( :] cc In article <1190290269.364040.120890@o80g2000hse.googlegroups.com>, > > In article > > <1190213176.294215.131...@n39g2000hsh.googlegroups.com>, [quoted text clipped - 13 lines] > crashing.... a real pane. > (-E: -= .....( :] Should have gone to the Apple store. > In article > <1190290269.364040.120...@o80g2000hse.googlegroups.com>, [quoted text clipped - 21 lines] > > - Show quoted text - their core memory wasn't compatible..... On Sep 18, 7:58 am, CarCrazy...@gmail.com wrote: > > * Replaced water pump (I deduced it went bad, replaced with genuine AC > > Delco unit) [quoted text clipped - 3 lines] > > If they did, it's spinning the wrong way. Interesting. Of course, the overheating issue began *before* I replaced the water pump. I only replaced the water pump because there was a high-pitched squealing sound (bearing going out) which is one indication that this pump's bearing is going south. And considering the old pump (just changed out) was a no-name brand (from China, with about 16k miles on it), I figured it probably had inferior bearings in it. (Also as a recommendation from a poster on my other thread). I used a stethoscope and it sure sounded like the pump's bearing was going out. However, the sound is still there, so it's probably the idler pulley's bearing. (Even with the stethoscope, it's difficult to tell if it's the idler pulley, water pump, or alternator - but that's not the point of the overheating :) On Sep 18, 10:59 am, james.r...@gmail.com wrote: > On Sep 18, 7:58 am, CarCrazy...@gmail.com wrote: > [quoted text clipped - 19 lines] > tell if it's the idler pulley, water pump, or alternator - but that's > not the point of the overheating :) ...and if the waterpumps are okay....then I agree with those looking for bubbles in the rad. cc On Sep 18, 11:30 am, CarCrazy...@gmail.com wrote: > On Sep 18, 10:59 am, james.r...@gmail.com wrote: > [quoted text clipped - 28 lines] > > - Show quoted text - don't know if this matters.... The last GM I worked on had two(2) temperature sensors. 1 on the top front, near waterpump, was for the emissions system. The other was for the temp gauge and it was on the right (passenger) side of the engine between the spark plugs. I don't remember which one controlled the fans. cc On Sep 18, 10:44 am, CarCrazy...@gmail.com wrote: > don't know if this matters.... > The last GM I worked on had two(2) temperature sensors. [quoted text clipped - 3 lines] > the engine between the spark plugs. I don't remember which one > controlled the fans. There probably are two sensors. There is one in the front of the water pump, which is the "Coolant Temperature Sensor" and I believe there is one on the driver's side side of engine. I replaced the one on the water pump, along with the pump, thermostat, and radiator cap and coolant mix. |
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