New 1991 Ecodiesel owner in need of some cooling system help.

[Kwaiin]

I recently purchased a 1991 Ecodiesel with 250k on it, pump is turned up, running about 20psi, 2.5" turbo back. Guy I bought it from gave me stacks of receipts. It was taken care of, runs great, he even drove it 2 hours to deliver it to me. Now, I put about 200 miles on it and one night it overheated on me, it had lost coolant. I did not know this until the light came on. So i pulled over and towed it home. Prior to this, earlier that day I did get a boost spike to 24 psi, it was just a broken vacuum line, I caught it quick.

I fixed the leak, filled the coolant, and fired it up. The upper hose is over pressurizing, or so it feels. If i take the cap off (cap is brand new) and let it run up to temp, upper hose is hot, lower is cold.

Now I fear the worst of it being a head gasket, I can do it but would obviously rather not. My other ideas are T stat, which ive ordered, or a clog somewhere in the system.

Any advice here on what I could do or any troubleshooting? This is my first VW diesel, and id like it to last. I love old cars, I know they arent perfect, so I expect problems, but Im not sure here.

[vanbcguy]

How quickly is it pressurizing? Within a few minutes of startup?

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[Kwaiin]

Yes within a few minutes. Lower hose does not get warm though, even if I let it run with the cap off.

[air-cooled or diesel]

is it possible you toasted the thermostat? it may not help, but the best i have right now is, try a new good thermo, youll prob need a new o-ring too, get a couple(o-rings). if lower hose stays too cold a new thermo under50% of the time be a possible cause/solve.

[Kwaiin]

I have a new t stat on order, I'm thinking that coulday potentially be it. I just fixed a couple leaks after it over heated on me. Im just concerned since I did manage to overheat it that my hear gasket may have called it quits.

[vanbcguy]

If it is pressurizing that fast then you are getting combustion gasses in your coolant most likely. Sorry to say but it sounds like your head needs to come off.

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[Dennis Froelich]

If you didn't refill your cooling system by the upper radiator hose to the head, you most likely have an air pocket in the system.
Filling your system through the resevoir creates an air pocket.

[Kwaiin]

Any links to a good write up on a head gasket job? And I didn't refill through the head. I had thought I may have an air pocket. I'll have to try to get all the air out.

[ORCoaster]

Kwain,  Best advice for doing a new Head gasket is to go get or find a copy in the library of the Bentley manual for this car.  With you being new to this engine I think that is the best course of correction.  Just to much to detail here in this forum.

[Kwaiin]

Just so happens I have a Bentley manual for this already. I just know that sometimes people find better ways to do a job. Guess I'm glad I have that thing now lol

[air-cooled or diesel]

the shop manual (bentley) is more than 90% correct. look 1st in faq's for adjustments/tweaks. they may be -buried in topics. variations arent too far removed from base(book), but come with experience, what works for you now you improve on, add to in further 'adjustments'. one of the things you get to learn is an order to your work, both with tools, as these and other older vw's didnt take many special tools, something each of these tools; 10mm, 13mm, 17mm, 19mm. there are some other close sizes you need, esp 8mm. etc,etc on the tools,, but one or sometimes 2 of each of these tools and you can what work on close to 1/2 the car, or more. of course you need combos(wrenches), sockets, deep sockets, and assorted, etc. as far as order, the manual outlines proper steps. read the comments, insets, and warnings, get to know outline of work, theres a whole section for head in shop manual, step by step.

[ORCoaster]

I have to second Air-Cooled on getting to know the process and outlining the tools and such.  You don't want to start removing the cam pulley for instance before you have locked all points in place.  TDC then IP then off with the valve cover for the plate behind the cam, in that slot.  That sort of thing. 

Knowing most of the next step versus reading the book and try to understand as you go can work for most people but if you get half an understanding first it will go a long ways towards getting the job done.

[thomas m]

I've been studying Youtube videos for general backround on engine work.

Here's one that I've archived for head work. May not be your exact model, but good for general orientation.

Dig around a bit yourself and you'll be amazed at what you can find.

I've found that researching helps a lot if one is not that experienced. It may, at times, seem overwhelming, but
it does eventually sink in. Using Bentley as a foundation together with all of the knowledge on this forum is THE way to go.

Here's the link:
https://www.youtube.com/watch?v=NhmousPg8Ig