Overheating Mystery, please help.

[55mpg06]

I don't know how true this is for your engine, but I have heard that on some diesels the return line to the resivoir (the small one) has what seems like "lumps" on it. These are some sort of one way valves that if they are plugged then there are many weird things that can happen. I would assume a way to check is to blow air through the line in the direction of the resivior.

Other thing, you should be able to get a resivior cap from a good sized car parts store like Lordco. It shouldn't be that expensive and from experiance it can be a source of all sorts of really crazy problems if it is faulty :? . Hope this helps. Keep us posted.

[Doug]

I see in one of your posts that you say the timing belt was removed. Have you confirmed that it was installed correctly and you are not out of time by one tooth on the belt? Could cause some serious overheating issues assuming that you have eliminated the cap, hoses, rad, head gasket, presurisation, air lock, slipping belt etc..

[spoooner]

My overheating mystery ($1000 and fifth mechanic) was a little tiny easy fix.  There is a restricter inside the hose coming off of the coolant reservoir.  Your can see this bulging, if not, feel down the hose until you feel it.  My mechanic pulled it out, and unclogged it.  That was it.

Symptoms were hard pressurized hoses, fan not working, only half the radiator was getting warm. etc...
Hope this is your prob.

[81 vw pu]

My overheating mystery ($1000 and fifth mechanic) was a little tiny easy fix.  There is a restricter inside the hose coming off of the coolant reservoir.  Your can see this bulging, if not, feel down the hose until you feel it.  My mechanic pulled it out, and unclogged it.  That was it.

Symptoms were hard pressurized hoses, fan not working, only half the radiator was getting warm. etc...
Hope this is your prob.

Hopefully he got it figured out, that was about 3 1/2 years ago!!!