Is this my thermostat leaking???

Me again. I’m sure I’ll be here every 3 days with a new problem.

Did 1060 km on the car after my most recent fix. Had thermostat replaced. Now I see a puddle below my car.

edit: deleted the engine oil leak comment... turns out it was a small coolant puddle accumulated below the engine drain plug.

Hard to tell from the pictures. The thermostat housing is at the front of the motor under the vacuum reservoir, behind the alternator. Also, if that is coolant on the floor, it looks green, not pink like G12 or G13, which should be used.

Those are pictures of coolant flange on the side of cyl head. If your valve cover or vacuum pump leaks oil it will swell the coolant flange seal and make it leak. Good time to change seals and coolant temp seal in one shot.

alright, I did some digging around. first off, I googled mk4 jetta thermostat before making this thread and was looking at the wrong spot, I thought it showed the thermostat at the driver side of the motor. guess not, my bad. I was looking at it wrong.




secondly, I just had it idiling for 20 mins while I looked around with a flashlight. it did not get up to full operating temp (90c). it only got to 60c before I was done looking around. I was able to find two spots leaking coolant. I dont know how to describe them so here is some pics. hopefully they show where. I can take more if needed. I drove 500km yesterday, then parked it, and it must of leaked like crazy all night because I came to the car in the morning to a puddle the size of my hand. today it barely seemed to drip. so maybe its worse when its at full operating temp?


the one is on the driver side right by the axle housing it seems. possibly a bad gasket. that one doesnt look easy to fix. its right beside where the frostheater is mounted (see pics)


the other is on the driver side by the lowest belt roller. I cant tell where that is coming from.


also, whoever recently worked on my car (2 mechanics) royally wrecked almost all 4 skid plate mounts. I know the rear ones are shot and the first mechanic used self tappers to hold it on via drilling right into the frame. not impressed. now I notice that my front passenger skid plate mount is broken too. I think this can be fixed by welding a new nut on there. im pretty sure this is a panzer skid plate.


also, on the skid plate where its leaking from the passenger side belt roller. there is a TON of wet debris accumulated on the skid plate...seems like its been leaking for months, years maybe even.


the coolant is orange, and it doesnt seem low.


what do I do?? (besides sell this damn car) I just had my first 1000+ km tank (1050 km. drove 91km with fuel light on) so I have a newfound love for it again.

I'd start by eliminating the coolant leak, the other stuff on the plate could just be coolant mixed with grime and slime. Interweb will be hard to help for that.
And upgrade your mechanic, you may want to fix the plate mount with new rivnuts. Could be a real pain getting the old ones out.

yeah the stuff on the plate is definitely that, I mentioned it because it looks like its been leaking for over a year judging by the crud on the skid plate thats built up. not too sure why its all of a sudden leaving a puddle on the road though. maybe it got worse.

I double checked and felt all the coolant hoses and they dont seem to be leaking.

Have you checked the power steering system? Any decent welding shop should be able to fix that skid plate mount for you.

fouillard13 said:

Me again. I’m sure I’ll be here every 3 days with a new problem.

Did 1060 km on the car after my most recent fix. Had thermostat replaced. Now I see a puddle below my car.

edit: deleted the engine oil leak comment... turns out it was a small coolant puddle accumulated below the engine drain plug.

Click to expand...

Do you see the 3 small hoses clamps? They look like they need to be clocked so they don't rub a hole in the larger hose.

A TDI doesn't warm up very well unless you drive it because Diesels are more efficient than gasoline engines.

havnt checked the power steering system... no idea how/where TBH. I did look closer and the leak seems to be coming from behind the large pulley on the very bottom, closest to the firewall. I believe thats the ac pulley?







anyways, I will clock those 3 hose clamps so theyre not problems in the future. there is decent amount of space between them, but you got a good point and it takes 5 seconds to do... cant believe the first mechanic would install them like that. my second mechanic (vw specialist) is good and wouldnt do that.

I drove the car 70 miles last night, got it to operating temp, and didnt leave a puddle this morning on the pavement. I sprayed brake clean on the leaking area by the frost heater and am going to keep a close eye on it. I did NOT spray any near the ac pulley because I was scared to get it on the belt.

still need to crawl under and get that damn mount dealt with though before I procrastinate too much.


those hose clamps remind me of this:

Those are the best clamps to use. Worm gear clamps are a fail in areas where large temperature fluctuations occur.

I think you may have an evolution import skid plate. Two aluminum posts in front with a machine screw through the plate and into the post?

Your skid plate looks like it has taken more BIG hits than mine LOL. I’d take the plate off, pound the corners flat with a 10 lb sledge, hopefully the holes still line up, drill and tap new bigger holes in the posts. If the bottoms of the posts are eaten out with corrosion so badly they can’t be fixed, shoot a line to evo, he can probably replace them, or maybe you have a friend in a fab shop who likes scotch. The posts just screw off, try a pipe wrench on them. They are dead simple, just an aluminum rod with a hole in each end.

I’ve used a big sledge to straighten mine when the engine was rubbing on it. Still on the original oil pan though.

Wilkins said:

I think you may have an evolution import skid plate. Two aluminum posts in front with a machine screw through the plate and into the post?

Your skid plate looks like it has taken more BIG hits than mine LOL. I’d take the plate off, pound the corners flat with a 10 lb sledge, hopefully the holes still line up, drill and tap new bigger holes in the posts. If the bottoms of the posts are eaten out with corrosion so badly they can’t be fixed, shoot a line to evo, he can probably replace them, or maybe you have a friend in a fab shop who likes scotch. The posts just screw off, try a pipe wrench on them. They are dead simple, just an aluminum rod with a hole in each end.

I’ve used a big sledge to straighten mine when the engine was rubbing on it. Still on the original oil pan though.

Click to expand...

yup youre 100% right. it is an evolution import.



my skid plate hasnt taken any hits... a few chunks of ice on the highways and the odd scrape from a deep rut once in a while (mostly on gravel roads/off road) but otherwise no it hasnt taken any big or serious dings.


he can replace them... for $90. im glad it can be taken off that simply though, thats good into. thank you!


wish I would of done it the other day when it was damn near summer time... we got 10" of snow last night and its COLD so its gonna have to wait till its nicer out in a week or so.


sounds like an easy fix if I can unthread that post though, very happy to hear that. the holes still line up perfect... just need the tiniest tack on the nut and its good to go, but if I can remove it ill get it fully welded. easy. $20 fix.