HWY driving,all of a sudden temp gauge rises, HEAT shuts off?? waterpump, heatercore?

hey guys so i need your help and knowledge on this one

was driving to the fiances house and about 5 min in without sound or warning the temp gauge started to rise relatively quick , and sure enough hit the red and the temp light came on so i pulled over and let it cool down. upon inspection i FOUND THE FOLLOWING

1) NO coolant leaking onto ground, so no hoses, clamps, reservoir fell apart and broke off.

2) The heat is now obsolete nothing at all , just blows regular cool air, AC works good just no hot air anymore? (heater core not getting flow, bad pump???)

3) inlet to the heater core is extremely hot as well as all the lines connected to the inlet hose, the outlet of the heater core i can grab by hand and isn't very hot at all (blockage in the heater core?? and the reservoir tank almost overflowed, it started to leak out of the bottom hose i believe do to back pressure from the heater core hence it overflowing and having extremely hot hoses)

4) UPDATE upon starting car and watching coolant reservoir i found there is no fluid return when motor is cold and warm, i read even on idle there should be coolant return before T stat opens up, i gassed it a few times to 3k rpm and no fluid came out ??? BAD WATER PUMP???

5) I'm just confused though as how my coolant reservoir almost overflowed, were talking 1" away from the threaded cap just inline with the sensor on a 45 angle, like if the return line isn't returning fluid how is this volume changing, reverse flow?? i understand everything else just dont get how i have fluid levels rising if i dont got no return fluids

if it is the pump im going to change it myself simply enough, or heater core i can back flush even

Start by checking if the passenger floor board is wet. Difficult to say what it is without more info.
If the floor board is wet heater core, however, there are a few other things to check before moving to the pump. Is there a broken T in the engine bay? Look at the back of the head specifically and check the small lines running out of it. Check all coolant Lines and especially the egr cooler to see if there's a leak.

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no circulation could be thermostat

Or water pump.

Do you see water flow on the tank?

X 2 on a failed pump.
Propeller loose from the shaft?

k_pt said:

Or water pump.
Do you see water flow on the tank?

Click to expand...

Only thing is that little hose can dump out the back side rather than to the reservoir. If the floor board is dry and the lines good then the pump is likely shot.
And be sure to check the dipstick for coolant in the oil.

Agree with everything here, especially liklihood of a failed water pump. However if it was me , I would replace the thermostat as well as the temperature sensor at the same time while the system is drained.

[Interweb guess] Sounds like the water pump impeller failed. It could be prudent to first check if the thermostat is completely failed in the closed position.

there is no flow back to the reservoir tank, the level used to be exactly at the maximum amount, but not it is half way between max and min, i will check the floor board when i get home in 2 hours as well as go under the car and see any T's came off.

there is coolant directly under the coolant reservoir going all the way forward to the passenger headlamp, which then drips down to the plastic skid plate we got

The T's will be under the engine cover trans side and back side. Especially by the vacuum pump and just behind it on the head, extremely difficult to see.

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i have read that if it is a head gasket issue to hold your hand over the coolant tank and wait to see if it pressurizes?i don't get that, if the cap is on the container it pressurizes so how is holding my hand over it any different?? and if its a headgasket would i not A) see a leak around the headgasket itself B) drain some oil like a litre and see if there is any coolant in it?

Headgaskets can leak in several ways:


Oil or water or combustion to teh outside
Water jacket to the combustion chamber.
Combustion to the water jacket


Combustion pressure are very high, so one of the commonest is to leak to the water jacket. No water in the oil that way, and no external leaks.


Remove the Tstat and see if this results in flow?

Head gasket can leak between cylinders, back of the head, etc., and not necessarily be visible just looking from the front of the car.

If everything is working fine, there is always a constant flow of coolant through the EGR Cooler, Heater Core and back to black metal pipe that enters the block below the Injection Pump (water pump housing that's cast in the block). Also, from the small hose coming off the back and end of the head near the coolant flange, there is circulation over to the Coolant Expansion Tank then off the bottom to the same metal black pipe. And, there is coolant flowing constantly from the coolant flange to the Oil Cooler and back to the same black metal pipe.

I tend to agree that this may be the typical slipping plastic impeller Water Pump. Once the engine cools down, it may work fine until it reaches that magic hot point and do this again.

Does the OP know if the Water Pump is of the plastic impeller type? Usually, replacement pumps have stainless metal, cast iron or brass.

waterpump and or bad t-stat or loss of fluid from leaking hose, your water system is draining somewhere and your boiling over and no coolant is getting to the heater core.

In 10 years working on TDIs, never seen a thermostat locked to closed, they always lock to open, but lets see ...

k_pt said:

In 10 years working on TDIs, never seen a thermostat locked to closed, they always lock to open, but lets see ...

Click to expand...

in the 6 years doing auto repairs like yourself i have seen plenty of t-stats that go bad in the closed position. its not often but it happens, usually happens more often in fords and Toyotas in my experience. Mostly likely OP has a coolant leak.
I rarely see waterpumps OEM go bad, its usually a tstat or hose. if proper coolant is kept in the system and healthy, waterpumps last almost forever, 250K is more than most cars see in a lifetime and this is where things start to go bad for waterpumps etc... So go figure.

Unless you have a plastic impeller water pump. I have mine that wore out the splines 15 years ago.
1. How long ago did you do the TB?
2. did you buy from a TDI club vendor?
3. Is the coolant reservoir oily and blackish?
4. How long have you had this car?

Post #9, leak found, might explain all symptoms.....

03tdiwagon said:

...............there is coolant directly under the coolant reservoir going all the way forward to the passenger headlamp, which then drips down to the plastic skid plate we got

Click to expand...

Actually, IMO, the leak just indicates the reservoir is over-pressurized due to overheating in the head. The leakage from the reservoir just follows the hose at the bottom up to the front, then drips off before it attaches to the hard line spigot next to the t-stat housing.

The real indicator is that there is no hot air in the cabin - one hose to the heater core is hot and the other cold indicates no circulation. That's a failed water pump, as several others have already indicated. And yes, sometimes even metal impeller equipped water pumps can fail.

If the t-stat was failed closed, and the water pump was working, the heater core would supply blast furnace type heat to the interior. T-stats are designed to fail open though, so a failed t-stat would most likely present as a failure of the engine to reach normal operating temperature.

Good luck with the fix. It is very close to as much trouble to replace the water pump as to replace the entire timing belt.

Cheers,

PH

I believe Powder Hound nailed it. (based on available info)

i got the car at 115k km it now has 125k km, i thought it was a good deal for 1800 bucks but turns out not so much.... i found a guy out in hagersville ontario who said he can do it for 150 bucks, change the waterpump. the shops name is SMOUTS GARAGE. anybody heard of him??

on the upside i am looking at another 2001 tdi jetta sedan tomorrow, 5spd, has 280k for $1000, isnt to rusted the guy mentioned it has half a tank of diesel thats been sitting in there for a year so i got to somehow get that out of there (any ideas other than syphon) and that it is hard to start in the cold (makes me thing glow plug or harness is bad)

Replacing the waterpump on these is the same as changing the timing belt - don't skimp on the mechanic. Whoever you select should treat this with the same level of care as a timing belt, with all the same tools.

I agree with the mechanic advice above. This is no time to skimp, as timing is critical. If the mechanics isn't a TDI guy, then a quickie water pump relacement will leave you with a car that won't start because the mechanic did a quick mark-and-pray and didn't know how to properly time it to finish the job.

As far as getting the diesel out of the car that has been sitting - you want to take a quick peek in the fuel tank. You do this by lifting the rear seat cushion, unscrew the 3 screws, and then you can probably use a large screwdriver to push the ring around the top of the tank to open it. You want to see if there's dark goop in the bottom of the tank. If not, then seal it back up and rest easy. Contrary to the chicken littles around this site, diesel can sit for years and still be good. The only 2 things bad that happen is water in the tank that lets algae grow, or too many microscopic asphaltines precipitating out. Either one causes black residue. The asphaltines aren't really that bad as they just form a very thin layer that sits on the bottom of the tank. Over a long period of time, they might clog the fuel filter. Microbial growth, however, will form deposits and goop in the water and will quickly clog the filter and ruin anything it sits in.

So, if the tank looks clean, you're good to go. You will probably have a larger problem in rusty brakes if the car has been sitting.

Good luck,

PH

Yeah, I'd open up the tank as Powder Hound has suggested and take a look inside. I sort of doubt you'll find much to worry about.

For what it's worth...

My RV has diesel fuel in the tank that's over a year old (40 or more gallons) .... no worries as the filter will handle it.

My mini excavator has diesel fuel in the tank that's over a year old (12 gallons) ... no worries as the filter will handle it.

My Dodge Cummins is used very little throughout a year, thus, at least a fourth to half of the diesel fuel in the tank may be a year old... no worries as the filter will handle it.

To have peace of mind, I'd remove as much of the fuel as possible. Dump in some fresh fuel with your favorite additive and after some use, change the filter.

Yep, as suggested, changing the WP should be taken serious as the procedure takes basically the same steps as changing the Timing Belt.... no short cuts. And, depending on the age/miles, this may be a good time to change the TB.

Might want to check for kits here:

https://roselandtech.ca/timing-belt-kit-bundle-alh

Might as well get it all done with all the needed parts while you are in there. Unless you have correct knowledge of when it was done last and by who and what parts were used. Parts can be had from stateside as well from or vendors here. At least that should inform you as to what should be replaced when doing a TB job.

03tdiwagon said:

i got the car at 115k km it now has 125k km, i thought it was a good deal for 1800 bucks but turns out not so much.... i found a guy out in hagersville ontario who said he can do it for 150 bucks, change the waterpump. the shops name is SMOUTS GARAGE. anybody heard of him??

on the upside i am looking at another 2001 tdi jetta sedan tomorrow, 5spd, has 280k for $1000, isnt to rusted the guy mentioned it has half a tank of diesel thats been sitting in there for a year so i got to somehow get that out of there (any ideas other than syphon) and that it is hard to start in the cold (makes me thing glow plug or harness is bad)

Click to expand...

You may end up with the same opinion on this one in time. Hard starting can be caused by low compression in a cylinder also, price accordingly. It was parked for some reason, assume the worst and buy lower than you can ditch it for, my opinion

You are considering buying another car with as many, or more issues. Think about that for a minute.

I agree with everyone else, find a good belt kit, or local trusted mechanic and give the $800-$1200 for a timing belt job. Check compression first to be sure it's worth it and if she has good compression as in a thermostat and should be good to go.

In the case of a new TDI that you don't know when it last had a new TB, especially one that has a failed water pump, consensus is that you're better off doing the entire timing belt job to ensure it's going to last and not have catastrophic engine failure.

If you don't want to spend the money on the belt job, you don't want a TDI, or VW for that matter. Any vehicle really, especially one with imposing valves, is prone to belt failure. You're better off knowing that part is good.

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Since there's been an external leak identified, the system is under-capacity, resulting in air pockets in the cooling system. Water pumps are decidedly terrible at pumping air, which explains many of the symptoms. Air pockets are very common in the MR2 cooling system, so I'm all too familiar with symptoms of air pockets (owned my MR2 for 16+ years and counting). No heat, temp gauge erratic and pegs out, some hoses hot, others cold.
Heater cores get coolant supply directly from the engine, and return directly to the engine, so a thermostat will not have any effect on heater core operation. Unless VW designed this cooling/heater core system differently from every other heater core circuit ever.

That's what I thought as well. But Powder Horn could be right, post #19, it's simply blowing out the bottle. Different problem, damn interweb...

Ok guys small update. 1) went through roseland technical services and talked with our man brian. WOWOWOW amazing. I made my order around 3pm on wednesday. I got everything delivered by 12:45pm the following day via purolator!!! I spent about 300 ball park on EVERYTHING and i found a tdi mechanic local to do the job was quoted 250 for the work so im happy there as well.

As for the sh*t box tdi i canceled upon arrival. The car had #1 and #3 glow plug reading infinite ohms so they were shot. Rust eating it out underneath, brakes GONE no fluid in resevoir at all. I pulled out the gas pump via the rear seat method and inside was alot or CRAP. It had so much residues idk what they did to the car or what was in that tank but man oh man im not talking a little algea or that black crappy stuff im talking blobs of this stuff immediately i said no deal im out

AND WITH GOOD NEWS THE NEXT DAY i found a 2003!! Alh TDI !!with a 5spd.....
Drum role pleaseeeeeeee it only had 195k km !!! Im getting it on sunday at 11am . I rented a uhaul trailer and i am gonna tow it back to my PLACE legally and not risk driving it as the ministry of transport is not open sundays to register it to my name . It comes safety and man is it clean ill upload some pics after i get it. The previous owner has a stack of reciepts since he owned it at 85k in 2007 so 11 years of records. Im very please. For 3300 safety etested 200k 5spd unicorn sedan. I cant be happier. Had water pump timing belt done 148k with reciepts. Has about 51k since done now under 200k on odometer Ill change it at 250k just for peace of mind