diagnosing a blown head gasket

[Empire]

since you dont have any fluid loss or mixing of fluids it sounds more like a faulty/bad coolant temperature sensor


coolant temp sensors are known to go bad in VW's

yeah, which is why the fans are on a manual switch
I know it is overheating, it blows steam/water out of the overlfow port and if it doesn't get to that point, the hoses are rock hard and in some spots, swelling...

[Empire]

you cant actually burp a VW cooling system as they dont have radiator caps.

All you can really do is fill the resivoir and then if the system drains that keep filling it till the fluid doesnt go below the fill line.

thats what I was doing before taking it for a test drive...
fill it, run it for a bit, let it cool, pop the cap, top it off. Usually took two or three times to get it to the point of being full.

[Empire]

Hmmm... but you said it stops blowing hot... when it over heats..?? sounds like a bad thermo stat.. . even a new one can fail.. i have had it happen on my type R...


My headgasket went out on my type R and i had no smoke, no water in the oil... mine was leaking pressure from the cylinders into my water jacket.. make me push all my water out the over flow tank..

the thermostat was my first thought... So I removed it and went for another test drive... still no dice...

and yeah, thats what appears to be happening. Start the car, instant bubbles/water movement. and a rougher than normal idle... I thought it was the timing being off from the recent tune up, and that is why it missed some at idle, but didn't above like 1,500 rpms...

[Garrett]

the thermostat was my first thought... So I removed it and went for another test drive... still no dice...

and yeah, thats what appears to be happening. Start the car, instant bubbles/water movement. and a rougher than normal idle... I thought it was the timing being off from the recent tune up, and that is why it missed some at idle, but didn't above like 1,500 rpms...

i almost want to say there is blockage somewhere but i dunno man. Im baffled on this one.


have you posted this on vwvortex yet? theres alot of very knowledgeable guys on there....

[Empire]

no, I'm not big in the VW's so i didn't know what forum was worth and shit or not...

but I'll head over to that one and see what they say...

thanks for the help!

[pdxblue]

If the flow stops suddenly after the temperature rises, are you sure you installed the thermostat facing the correct direction?

(disclaimer: I'm an MGB guy who noticed this thread off a Google search, no idea whether your thermostat can be installed backwards. Mine sure can be.)

[_Charles_]

Compression checker would be #1 on my list. always best to rule that out first. At least after a compression check, you will have an solid idea where to start. When I had my turbo Honda, I kept it in my car...I once pulled over after leaving desoto and did a compression check on the side of the road. My friends thought I was crazy...but it made me feel better.

Charles

[Empire]

If the flow stops suddenly after the temperature rises, are you sure you installed the thermostat facing the correct direction?

(disclaimer: I'm an MGB guy who noticed this thread off a Google search, no idea whether your thermostat can be installed backwards. Mine sure can be.)

no, it is well after the temp rises...
you might be able to force it to go in backwards... seemed pretty straight forward to me...
but, it isn't the thermostat as it has been removed trying to diagnose the problem...

[Empire]

Compression checker would be #1 on my list. always best to rule that out first. At least after a compression check, you will have an solid idea where to start. When I had my turbo Honda, I kept it in my car...I once pulled over after leaving desoto and did a compression check on the side of the road. My friends thought I was crazy...but it made me feel better.

Charles

yeah, I know the feeling...
the jetta doesn't lend itself to an easy compression check though.. you have to pull the manifold just to get to the #2 and #3 plugs... annoying...

But, I'm working on getting this car sold so it isn't my problem anymore...

[senor honda]

It's my understanding that thermostats open and close, but they don't control direction of water flow.

When I have doubts as to whether they open at the right temp, I test them.

Some thermostats ....since they are round can be mounted upside down, however.........If a t-stat has a small hole at the edge, that hole should be at the top as mounted in the engine...........sometimes the hole has a small jiggler in it, but the hole allows air to escape from the system.-Bob

If the flow stops suddenly after the temperature rises, are you sure you installed the thermostat facing the correct direction?
(disclaimer: I'm an MGB guy who noticed this thread off a Google search, no idea whether your thermostat can be installed backwards. Mine sure can be.)