Overheating problem!!!

Hey pals, I've been a while out of the forum due to my work and because my jetta has been working like charm until NOW!!

I have a MKIII 1997 GLX VR6 with automatic transmission (01M), it has 76k miles driven.

Well, as I told you it was working fine, until a month ago. I was driving on the road and suddenly the temperature warning light started blinking, the temperature clock was in normal position but oil temp was 230F. Stopped in the nearest gas station and the coolant level was low. Didn't turn off the engine, put like a gallon of water on the tank (maybe half of the gallon was spitted off by pressure) and replaced the cap. Continued my driving and like 20 miles after the light blinked again. Look for a place to pull over, temp clock again normal, but oil temp 270!!!!. The tank was again dry, this time was very difficult to refill, the steam throwed away almost every water I used to refill. I showered the engine, while working, the temp went to 190, I stopped the engine and call for a platform truck to take the car. This is not all.

Well my car went directly to the garage and my mechanic told me that I burned the head cilinder gasket (not surprised about that, the engine was boiling!!) The cilinder head was tested and the test didn't showed any fractures or bending? (is this a correct term?), he replaced the gaskets, torqued the bolts as directed (yes in the three steps) and removed the thermostat believing that this was the cause of the primary overheating.

The engine started easily and runs very smooth. He let the engine run for 2 hours idling. No leaks, put the cap on the tank and took the car for a ride. 5 miles away form the garage the light began to blink, he reterned to the garage right away and surprise!!!, the tank was EMPTY!! After that the radiator has been cleaned up (at a radiator repair shop) water pump has no leaks, hoses are ok no leaks either. The car starts and run for a lot of time unless you close the coolant tank. When the system gets pressure it begins to blow the water or coolant through the vents in the tank. We don't know what else to do. The gasket has been tested for leaks, apparently there are no leaks of pressure through the gasket and the engine runs fine.

Please anybody help!!!

Well thats odd, I have not seen a head gasket go bad on that year.
To me, sounds like you might have a blockage or a water pump failing. You need to check the water pump, secondary water pump, and for a blockage in your coolant system.

Ok, tips to do it, we have checked the hoses, the radiator is clean, you can see the turbulence in the return hose at the tank when you step on gas. We have checked the transmission intercooler it has no resistance (tested with an air compressor. So, you think the next step is to check the water pump? we wil try that. another thing, where is the auxiliary pump located?

BTW, the engine is running without thermostat

The auxiliary water pump is under the air filter box hose. You will need to remove your air filter box out of the way. It is make it alot easyer to see and work on. You will see two coolant hoses and one connector on top attached to the auxiliary water pump.

One way to check to see if it is working, let the car run for alittle bit and then turn the car off. The auxiliary water pump aways runs for alittle bit after the car is turned off.

Ok thanks i'll try that tomorrow, I don't have the car here is at the garage. My car has the neuspeed cold air intake system so I think it would be easier to locate the pump.

Thermostat..... The original cause of the overheating. Dont think a head gasket was the original problem. shop problably wanted the 1500.00 for the job, if they even put a new one on. and if the gasket WAS replaced than the head had to have been resurfaced because the only reason the gasket goes bad is from a warped head. so if they just replaced the gasket, it problably blew in the first 5-miles.
The coolant resivour caps also are problems on theese and are about 25.00 i think at vw for a new one.

If they did not replace the thermostat than do that.

@veedubmechanic. I've seen your posts and you have all my rispect, I think that you really know what you are talking about. But let me tell you something about my car. Yes, originally we thought that the cause of the overheating was the thermostat. My vr6 has an 80 centigrade thermostat but the thermostat is ok, so anyway the car is now running without thermostat. The head gasket really was blown. The place where the car is being repaired is not a public garage is my personal mechanic, we do the job together as my hobbie, he does the rough part and the tools, I do the brains an something not so hard. We did a cilinder test before trying to take head off, It failed in 4 of 6 cilinders. We send the head to a repair shop and they told that the cilinder head was not cracked, and that it has an slight warp o bend?? i don't know how to tell that (native language is not english) of about 10 microns?? that it was between the tolerance ratio and if they resurface the head maybe it won't fit ok. So we installed the head with a new gasket. Started the engine and the car runs awesome, no misfires, good acceleration, the cooling system has just water in this moment, we removed the thermostat and tested by boiling it. The car has being running for something like 10 hours in total with no problems, you just have to put the cap on the tank and the car begins to throw all the water, coolant or whatever you have in the cooling system through the vent holes not through the cap. We did a new cilinder test thinking of what you are telling (maybe the repair shop didn't tell the truth and the head is ****ed up) but this time the test was ok. Do you think is the cap?, the cap was cracked a year ago or so and I replaced with an original VW cap that is what I am using now. Please any other ideas??

@femalevwtech I may sound dumb to you but I didn't find the aux pump!!

I do have something under the filter box but it looks like a canister. Don't have any connections just hoses and looks like vacuum hoses, not coolant.

Thanks for your help

No. Thats ok, I might not have been clear or told you the right place. I might have my VR6 engines mixed up.

Check on top of you raditor fans, it should be closer to the pass fan. If it is not there, than look at your coil pack for your sparks. Look behind your coil pack. You might have to removed the engine cover to see it.