>>Your thermostat is probably stuck shut.
>
[quoted text clipped - 3 lines]
>>>radiator is COLD after driving for 1/2 hour. Temp gauge always on COLD.
>>>My water pump ?
> It sounds like the engine is heating up and the heated coolant is getting
> TO the radiator but not THROUGH it. Generally though, the coolant flows
[quoted text clipped - 7 lines]
>
> Stephen N.---> more than enough though, it seems...
Doesn't coolant flow from the bottom hose TO the engine, then through the
thermostat back into the radiator? If the t'stat is stuck open, the temp
will be higher on the top hose and cooler on the bottom because the water
doesn't have enough time in the engine to get up to temp, then looses what
heat it did gain traveling down through the radiator, as is the case here, I
believe.
SC Tom
Stephen N. - 25 Oct 2006 17:26 GMT
>>It sounds like the engine is heating up and the heated coolant is getting
>>TO the radiator but not THROUGH it. Generally though, the coolant flows
[quoted text clipped - 14 lines]
> heat it did gain traveling down through the radiator, as is the case here, I
> believe.
Depending on the vehicle, it is sometimes possible to see the direction
of coolant flow into rad through the top hose.
Here's a simple diagram of a coolant schematic. I couldn't vouch for
the system in question but I think most are similar to this one.
http://ep0niks.ctech.ca/vw/eva2/GE02/ch1.html
Stephen N.---> prolly anyway...
SC Tom - 26 Oct 2006 02:06 GMT
>>>It sounds like the engine is heating up and the heated coolant is getting
>>>TO the radiator but not THROUGH it. Generally though, the coolant flows
[quoted text clipped - 24 lines]
>
> Stephen N.---> prolly anyway...
I guess it is vehicle dependant. This was the one I was thinking of:
http://www.binderbulletin.org/faq/3.htm#3
SC Tom
Stephen N. - 26 Oct 2006 02:34 GMT
> "Stephen N." <Steelystephen@coldmail.com> wrote in message
>>Here's a simple diagram of a coolant schematic. I couldn't vouch for the
[quoted text clipped - 5 lines]
>
> http://www.binderbulletin.org/faq/3.htm#3
Well, that seems quite opposite doesn't it? Coulda bin one of those
stupid arguments between two lesser fellas eh? lol...
Stephen N.---> 'course your site's prolly rong...
David M - 26 Oct 2006 09:53 GMT
>>>It sounds like the engine is heating up and the heated coolant is getting
>>>TO the radiator but not THROUGH it. Generally though, the coolant flows
[quoted text clipped - 24 lines]
>
> Stephen N.---> prolly anyway...
In your link, it is not possible to tell which hose is the
top and which is the bottom.
If you read a little further down, your link says:
http://ep0niks.ctech.ca/vw/eva2/GE02/ch4.2.html
A thermostat stuck open will cause the engine to warm up slowly and run
below normal temperature at highway speed.

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David M (dmacchiarolo)
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Stephen N. - 26 Oct 2006 17:42 GMT
>>Depending on the vehicle, it is sometimes possible to see the direction
>>of coolant flow into rad through the top hose.
[quoted text clipped - 14 lines]
> A thermostat stuck open will cause the engine to warm up slowly and run
> below normal temperature at highway speed.
It's true the hoses are not marked as top and bottom but in my limited
experience I've usually found the thermostat to be on top of the engine,
connected to the top of the rad with a fat hose. This was also true of
Mitsubishi 4cyls common in Chrysler cars and minivans.
I have to admit this is mostly on older V8's and inline 6's and I
haven't had to have a good look at the coolant system in my truck.
But back to the OP's observation. He says:
>Upper (left) big hose is HOT and the lower (bottom Right) hose and
>radiator is COLD after driving for 1/2 hour. Temp gauge always on COLD.
>My water pump ?
If the top hose is hot it can only have been heated by the engine.
If the rad is cold then hot coolant is not flowing through it.
This suggests there is little or no circulation and that points to:
- a thermostat that is stuck closed
- a water pump that is not circulating coolant, or
- inadequate quantity of coolant.
Of those, only a non-operational temp sensor or lack of coolant would
cause a cold temp reading.
I can't think of what other causes there may be.
Stephen N.---> but I never said I had all the answers...
David M - 26 Oct 2006 09:46 GMT
> Doesn't coolant flow from the bottom hose TO the engine, then through the
> thermostat back into the radiator? If the t'stat is stuck open, the temp
> will be higher on the top hose and cooler on the bottom
That's the symptoms the OP reported.

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SC Tom - 26 Oct 2006 11:20 GMT
>> Doesn't coolant flow from the bottom hose TO the engine, then through the
>> thermostat back into the radiator? If the t'stat is stuck open, the temp
>> will be higher on the top hose and cooler on the bottom
>
> That's the symptoms the OP reported.
". . . down through the radiator, as is the case here, I
believe."
That's what I was alluding to at the end of my reply.
Have a good one!
SC Tom