 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
Car Forum / BMW Cars / March 2005valve job or just head gasket?
I finally found out why my 325i (1993) was pinging like it was running on crappy gas (which it was not). The local BMW 'expert' mechanic told me he found a very slight amount of coolant on two plugs. My other mechanic did not make any mention of it at all, although after running it on a scope, replacing a few nickel and dime possibilities, it still made the pinging, but only when reaching operating temp. This 'expert' told me that since it has 174,000 miles on it, I might as well throw in a used long block for the price of $4300. Ummm......no. That is not going to happen. My question is, based on the fact that it is only a head gasket and not any damage to the head, would swapping the head gasket suffice or am I looking at more of a major issue? If it is cracked, warped or anything else, I know the answer already. Is there anything wrong or incorrect about just replacing the gasket and keep driving? It was not missing or overheating when I brought it in. Simply just the noise and not too bad at that. In the mean time, it has been recommended by my local BMW chronie to put some gasket fixer in the radiator and drive it. What are your thoughts besides junking it? Thanks. I had a similar experience with my 88 325is. Similar answers, too! The coolant had worn a worm-like pattern inside the connecting rod bearings and caused a solid "thunking" when accelerating heavy in low RPMs. Anyways, I replaced the connecting rod bearings in all 6 rods. PROBLEM SOLVED. I also replaced the oil pump and the whole thing ran under $100.00 (did work myself, own tools, nothing hard, engine in car). Process took 4-5 hours because I went slow. Seems the previous owner had a head gasket failure and didn't check the bearings before replacing just the head gasket. The engine was flawless after that. No leaks, good cylinder pressure. Bill 86 535i > I finally found out why my 325i (1993) was pinging like it was running on > crappy gas (which it was not). The local BMW 'expert' mechanic told me he [quoted text clipped - 16 lines] > > Thanks. >The local BMW 'expert' mechanic told me he found a very slight amount of >coolant on two plugs. My other mechanic did not make any mention of it at >all... A coolant leak is best diagnosed by pressure-testing the cooling system. Oil analysis will tell you if coolant is getting into the crankcase. If you're going to spend the cost of R&R'ing the head, you might as well have the machine shop check it for warping and do the valves. If I do the valve job, will I blow out the bottom end with 174k miles on it? I am going to pressure test the cooling system for sure. Will the coolant in the rod bearings cause major issues if it is not fixed right away? >>The local BMW 'expert' mechanic told me he found a very slight amount of >>coolant on two plugs. My other mechanic did not make any mention of it at [quoted text clipped - 5 lines] > If you're going to spend the cost of R&R'ing the head, you might as well > have the machine shop check it for warping and do the valves. 1. compression test cylinders (may tell if coolant pressure test will leak into cylinder) 2. pressure test cooling system 3. check oil and plugs for coolant 4. change your oil and filter if coolant suspected in oil Coolant will eat away areas on rod bearings closest to journal (where oil comes out to bearing first). This will also cause a longer than average oil pressure light to stay on while building pressure. It may be a few extra seconds, but the concerned owner will notice it and it will gradually get longer as more material is dissolved. I estimate mine went just over a year before I got concerned, and 900 miles from home. Luckily, the crank was undamaged, due in no small part to my 3,000-mile oil changes. Bill 86 535i > If I do the valve job, will I blow out the bottom end with 174k miles on it? > [quoted text clipped - 10 lines] > > If you're going to spend the cost of R&R'ing the head, you might as well > > have the machine shop check it for warping and do the valves. > If I do the valve job, will I blow out the bottom end with 174k miles on it? > > I am going to pressure test the cooling system for sure. Will the coolant in > the rod bearings cause major issues if it is not fixed right away? No, the bottom end is near bulletproof. Your risk to it is from contaminated oil resulting from not fixing the head. I did my head gasket at 335,00km. You could still see the cross-hatches on the cylinder bores. -Russ. >I finally found out why my 325i (1993) was pinging like it was >running on crappy gas (which it was not). The local BMW 'expert' [quoted text clipped - 16 lines] > BMW chronie to put some gasket fixer in the radiator and drive it. > What are your thoughts besides junking it? A couple of thoughts... First, I would definitely get a second (or third) opinion before I made any rash decisions. Have the engine tested for cooling system leakage. The expert detecting coolant and then recommending a complete rebuild sounds a bit fishy to me. Second, if it turns out that you really do have coolant on your plugs, you need to remember that a head gasket seals three seperate environments within the engine. The combustion chamber, the oil galleys and the cooling system water jacket. A leak can occur between any two or all three. The wet plugs would seem to suggest a leak has occured between the water jacket and combustion chamber, *BUT* when that happens there is usually a completely different symptom. Think about it with me: The pressure in the cylinder during combustion is *much* greater that the pressure in the cooling system even at full temperature. That means that the "normal" symptom of a leak between cylinder and water jacket is the over pressurization ofthe cooling system without actually overheating. In other words, even the cold engine will have high cooling system pressure. The cooling system can be tested for the presence of exhaust gasses to rule that out. It's also possible to lose the seal between the oil and coolant but not breach the combustion chamber seal. The difference in pressure between the oil and coolant is not much, so if a leak occurs between those two you can get oil in the coolant and/or coolant in the oil. The oil and coolant can both be tested for contamination. Thirdly, rather than a $4300 short block, I'd be seriously looking for a low to mid mileage used engine at the junkyard. Heck, a nice M3 engine would make a worthwhile drop-in project. There seems to be no shortage of M3's with smashed-up bodies that could be good engine donors. -Fred W > I finally found out why my 325i (1993) was pinging like it was running > on crappy gas (which it was not). The local BMW 'expert' mechanic told > me he found a very slight amount of coolant on two plugs. I'd love to know how he did this. Is it losing coolant? Head gaskets, etc, don't weep slightly.  Signature*The man who fell into an upholstery machine is fully recovered.* Dave Plowman dave@davenoise.co.uk London SW To e-mail, change noise into sound. I don't know how he did this. I am not an expert by any means, so I took it to this place called Benz n' Beamers in Harbor City, CA. I don't know if he was trying to rip me off or not. >> I finally found out why my 325i (1993) was pinging like it was running >> on crappy gas (which it was not). The local BMW 'expert' mechanic told [quoted text clipped - 3 lines] > > Is it losing coolant? Head gaskets, etc, don't weep slightly. A cracked head. A distinct possibility if the car seriously overheated in its past. R / John This really sucks considering that I am going to Scottsdale AZ in May and don't have the funds to replace the head at the moment. Scottsdale gets to about 110 to 115 in the Summer so I am sure to destroy the car by that time. I figure I will just drive it and pray until I get the funds to do something about it. If I do this, I am sure I will be able to afford an engine from the junkyard by October. An 'M' series engine would be nice. What mods do I need to do in order ot have it work? >A cracked head. A distinct possibility if the car seriously overheated in >its past. > > R / John > This really sucks considering that I am going to Scottsdale AZ in May and > don't have the funds to replace the head at the moment. Scottsdale gets to [quoted text clipped - 3 lines] > engine from the junkyard by October. An 'M' series engine would be nice. > What mods do I need to do in order ot have it work? My advice: If it looks like you're going to have to do a rebuild - don't do it. Instead, call around to local junkyards (especially ones without computer inventories) and find a wrecked BMW with a low-ish mileage engine, especially one that you can start and run before buying (though they'll charge a bit more for such an engine, of course). You can probably get the whole junked car (minus any resellable window glass) for way less than half of the cost of a rebuilt engine. If the junker is an E36, you might even be able to snag some spares or swap some parts - carpet, seats, windows, stereo, ECU, wheels, tires, battery, exhaust, etc. I did this with an old Mk I VW Golf GTi. I pulled a complete blue interior from the totalled VW to replace the mildewed and ugly burgundy one in my "racing" GTi, plus four alloy wheels and tires. I had pre-negotiated a cash price of $100 for everything I could pull off the car - they didn't care. They were gonna crush it. Engine swapping requires an engine hoist; but they're not expensive to buy. You can probably have the guys at the junkyard pull the motor for you and drop it (carefully) into a waiting pickup bed for hauling to your shop. If you don't have suitable work space, talk to a local friendly garage owner about renting after-hours shop time. Sometimes they'll do it. Of course, better yet would be to talk a local mechanic into doing the work for you after hours, for cash of course. Think of it as an automotive adventure... R > > This really sucks considering that I am going to Scottsdale AZ in May and > > don't have the funds to replace the head at the moment. Scottsdale gets to [quoted text clipped - 30 lines] > > Think of it as an automotive adventure... Just be aware, you could be buying somebody else's marginal motor. If you do the work yourself, the parts required for a head job are worth a couple hundred, maybe a couple hundred more for any machining that is required, and technically it's simpler than an engine swap. When you rebuild your own, it's the devil you know. When you buy used, you roll the dice. Not that the rest of your points re: ancillary parts aren't good ones, just with a motor you can run it and still not really know what you're dealing with inside, low miles or not. -Russ. |
Reply to this Message |
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2008 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.