Coolant Loss, Stranded in LA

I'm an doing some work in LA but I live in the Bay Area. On the drive down I5 the car was fine but when I hit the grape vine it over heated. I pulled off to the side and let it idle to cool down enough to make it to the next rest stop. When I got there, the coolant was HOT! I only un-threaded the cap just enough to release some pressure and let the steam boil off. The coolant tank was empty so I topped it off with water (all that I had) then started on the road again. The low coolant light came back after a few miles but temps didn't rise for several miles after that. At this time I stopped at a Walmart and picked up some VW spec coolant to top it off. When I got back to the car, there was a puddle underneath and the tank was empty. I refilled and went on my way. I made it to my destination and parked it but when I came back there was coolant underneath on the passenger side. I checked into my hotel and now I'm trying to figure out my options.

Here are some of the things I know...

1. This is not the first time I've had issues with leaks. I've had coolant loss issues before, I replaced the coolant tank and but did not appear to solve the problem. It is very intermittent. I went several months without any leaks but today was the first day the leaking returned in months.

2. The loss appears to be very close to the coolant tank. I can see evidence of coolant under the tank but because of how much stuff is there, I can't see any obvious places it could be coming from. The water is traveling down the channel that goes from the engine bay and runs under the passenger side of the car. It eventually drips out a drain hole on the passenger side near the middle of the car.

3. It leaks when the car isn't running.

4. Opening the coolant tank the coolant system is under a vacuum as I hear the air being sucked back into the system.

5. The car has 330k miles on it and the coolant hoses that go to the coolant tank have not been replaced as far as I know.

With this information, are there any obvious culprits to check in the general area of the coolant tank other than the tank itself which has already been replaced? I can replace the hoses if that is the issue assuming I can find something suitable at a local parts store but I've got no tools on me so I'm limited in my troubleshooting and repair abilities.

adamis said:

2. The loss appears to be very close to the coolant tank. I can see evidence of coolant under the tank but because of how much stuff is there, I can't see any obvious places it could be coming from. The water is traveling down the channel that goes from the engine bay and runs under the passenger side of the car. It eventually drips out a drain hole on the passenger side near the middle of the car.

Click to expand...

there's a screwdriver in your spare tire kit, take out the two phillips screws and look under the coolant res

If it is leaking you can patch it over with any sort of epoxy

just leave the cap completely off and it'll leak slower as it won't pressurize

Thanks, didn't realize there was a screwdriver there! I took a picture and this is what I was able to see. This looks like it's from the overflow line of the coolant tank. I couldn't see any other obvious areas that fluid might have been flowing or leaking.

https://photos.app.goo.gl/y9NXCth3FxyDBJTb6

From what I can see, it looks like there is an overflow line on the side of the reservoir that it is leaking out of? But then, how does that work if the system is pressurized? And why would the coolant still leak out from this spot if the car was parked?

Thanks

If you've replaced the coolant tank recently, could it be the lines themselves are cracked and leaking coolant somehow? or maybe the hose clamps are not tight enough?


Since you say it leaks when the car's not even running, I think the bottom coolant line is the more likely culprit.

I had an issue with the little nipple at the top on the return line, it was cracked and sprayed water. However you said you replaced the coolant tank. Provided you didn’t crack that nipple during installation, I’d agree with Alex, bottom hose or cracked lines.

The cap is designed to seal until it overheats, or the coolant capacity is exceeded then out the overflow goes through that passage.
It overheated and either is still doing so, is dripping out afterwards, or you have an issue with the cap not creating a good seal if it continues to be an issue.
That nipple at the top does like to break and spill coolant.

I recommend a minimum of a new thermostat and check the water pump isn't slipping and/or otherwise bad.

Sent from my Armor_2 using Tapatalk

Thanks for the suggestions so far. I remembered I had the radiator replaced a couple of years ago as it was leaking. I'm not positive if the hoses were replaced then or not. They don't look overtly bad though, no obvious signs of cracking.

I am kind of leading towards some sort of blockage either in the engine block or the radiator though. The reason I'm thinking that is that a few times the water light comes on and when I open the hood, the reservoir is empty but when I unscrew the cap, I can hear air being sucked in and then water comes back up into the reservoir at about the right level. Where this vacuum is coming from I think is the key to the problem. I've had the timing belt replaced with the new water pump kit though I'm getting very close to needing to replace again.

I think I will have to look into a shop that can do a radiator flush and an engine block flush to see if there really is a blockage. Are there any good TDI mechanics in the LA area I can go to?

Doubt that it is vacuum, but instead pressure (from the level coming back up)

Do you have good heat output from the heater core when the coolant is full?
If not then it may well be the water pump has failed (plastic impeller falls off the shaft) causing overheating, and then the coolant boils and is pushed out the relief hole to the bottom of the res.

Fill it completely by the lower radiator hose then start and fill until full. No way a vacuum is there, kinked heater line is though.

Sent from my Armor_2 using Tapatalk

I don't know where you are in L.A. but I'll be around home today if you need a place to work.

Thanks for the offer. I'm going to see if I can make it home tommorrow. I plan to stock up on lots of fluid. If I can make it over the grapevine I think I can make it home.

Don't bother with actual coolant if it's leaking, just buy cheap distilled water and keep dumping that in

Sounds like more than one thing's wrong here. Hope you make it home safely.

Noted, I'll buy some jugs at Walmart.

I've looked again and still no obvious sign for where it can be leaking. I'm considering the following idea... Maybe there is no leak at all and I truly am chasing a ghost. It could be that when the car overheated, it poured a bunch of fluid into that channel that runs down the wheel well and underneath the passenger side bottom of the car. Maybe there is so much dirt and grime / grease in that channel that enough fluid was retained such that it looks like it is constantly leaking but it is just what is releasing from the grime over time. This might be why the problem eventually went away I suspect. I am leaning this way because as much fluid that appears on the ground, it seems there should be an obvious sign of leakage under the reservoir or the hoses that connect but there isn't.

The reservoir going empty while driving but then filling back up when I open the cap could be an entirely different issue of a plug somewhere else. That would also explain why I overheated going up the grape vine in the first place. Could be a partial blockage such that I have just enough cooling capacity for normal day to day driving but prolonged climbs overwhelms and causes the heat to build up.

That's the best I can come up with at this time...

Hello, when coolant reservoir was opened hot, then closed - there will be any pressure after long drive because of absense colder air, nothing to heat up and pressurize. After cooling down air is sucking inside ant next warming cycle pressurizes air again.
Possibly leak is from thermostat housing or metal tube comming into block near thermostat, or pump itself? Could be old hard rubber O-ring, as I have in coolant flange driver side. Leaked only cold and stopped when in reservoir builds negative pressure due to the lost liquid (0.5L)... In my case helped cyanoacrylate moment glue on O-ring, without disassembling. I worked when air was sucked to reservoir, so no leak at that time... In more time could help brake fluid or power steering fluid on O-ring, it rejuvenates rubber...
In Your case could be hardened thermostat O-ring.
Sorry for bad english...

I suspect you have a failed head gasket. That would explain the symptoms you describe. Drive it easy on the way back and you may be OK. You've got a good guru in SF (you probably already know him) who can help you diagnose and fix the problem.

A coolant system pressure checker may be a good investment along with the adaptor for the vdub cap. Pump it up to the same pressure as your cap and see if it holds for 15 minutes. If it drops, coolant should be evident. If it drops with no coolant evident, listen under the fill cap and through the dipstick. Also Check your oil to see if you gained any on the dipstick.
Pressurizing the system can show you small leaks that are not evident otherwise, hopefully.

IndigoBlueWagon said:

I suspect you have a failed head gasket. That would explain the symptoms you describe. Drive it easy on the way back and you may be OK. You've got a good guru in SF (you probably already know him) who can help you diagnose and fix the problem.

Click to expand...

Are you referring to Matt or someone else? I actually don't know the guru's in this area. I went to a couple of GTGs a while back and had Justin do my timing belt for me that was years ago.

For what it is worth, in 2014 I drove my ALH Vanagon from about Madison, Wisconsin to Alaska and back home to Kentucky, with no cooling system pressure without any issues at all.

Reason: My cooling system pressure monitor (gauge) tubing failed near the gauge releasing all the pressure. It was going to be a PITA to repair. So, I just drove on and never had to add any coolant... no over heating, etc.

The typical pressure I see is between 7 and 10 psi. If I release the pressure when the engine is hot (warm), and then re-tighten the cap, under normal circumstances, the pressure will never rebound to the level it was when I released the pressure. That's what I've observed on my pressure gauge.

I agree........no vacuum on the system.

Well after thinking about it, I've concluded that the reason I overheated is likely because I have rust in my cooling system. I'm thinking this because of two things... The first being that when the car runs, the reservoir tank empties leading me to conclude that there must be a partial blockage somewhere causing water not to flow correctly. The second clue is that I've noticed the heat doesn't get nearly as hot as it used to in the mornings when it's cold outside. I must have just enough cooling capacity for low load drives but the grapevine pushed it too hard.

So, I've ordered some Thermocure radiator flush and will be running that in the car for the next week to hopefully get that rust flushed out. I'm headed back down to LA on Sunday so hopefully I get the bottle in time to get it added to the system. I'll post back my results in a week or two.

Well after thinking about it, I've concluded that the reason I overheated is likely because I have rust in my cooling system. I'm thinking this because of two things... The first being that when the car runs, the reservoir tank empties leading me to conclude that there must be a partial blockage somewhere causing water not to flow correctly. The second clue is that I've noticed the heat doesn't get nearly as hot as it used to in the mornings when it's cold outside. I must have just enough cooling capacity for low load drives but the grapevine pushed it too hard.

So, I've ordered some Thermocure radiator flush and will be running that in the car for the next week to hopefully get that rust flushed out. I'm headed back down to LA on Sunday so hopefully I get the bottle in time to get it added to the system. I'll post back my results in a week or two.

Offer still stands for Sunday if needed.
Monday I won't be around until about 3-4 PM, though.

Is the coolant in the pic green? Suppose to be pink. The two are not compatable and will gum up the cooling system if mixed.

" I stopped at a Walmart and picked up some VW spec coolant to top it off"

I was unaware Walmart sold vw coolant.

It's Prestone Coolant formulated for European cars with VW specifically listed. May not be perfect but it's the only thing I was going to find at the time. At home I have the pink fluid I use but the coolant is green from using tracer dye to try to find the leak hence why it looks green.

The coolant hose (small one) going into the top/side of the expansion tank comes directly off the head just below the coolant flange. There is a small stainless steel pipe in the end of the head that the small black rubber hose connects to. It's sort of "independent" of all the other hoses. There is always coolant circulating through that hose. It empties into the expansion tank. From there, coolant goes out the bottom of the expansion tank over to a metal black pipe (near the dip stick tube). The black pipe goes to the back of the water pump housing (cast as part of the block). There, the coolant by-passes the T-stat and goes directly into the block and makes it's way up through the head and back to the small pipe.

So, if your engine is not circulating coolant as I explained above, it is either terribly plugged or the water pump is not functioning. It's as simple as that.

As for incompatible anti-freeze, yes, the older green will not mix. It will turn to Jello and tend to plug things like the Rad and Heather core. However, I'm of the opinion that the new green (doesn't taste sweet) may be compatible. I do have a 50 - 50 mix sitting out in my garage that has not jelled. I mixed it over a year ago....

Is the expansion tank stained with red rust?

Back in LA again and back to the same issue. Long story short... thinking it was a rusty radiator (~2 years old) I put the Thermocure rust remover in before I left. Car ran fine for about 100 miles, I had my OBDII plugged in and was reading temps around 167 degrees, no problems. Then I got into some stop and go for about 20 minutes and the car started heating up. It went up to about 210 degrees so I turned the heat on inside the car and the temps came down to about 185 degrees but would not go lower. What's odd is that for a while, it seemed like I could see the thermostat open because the car would creep up to about 200 and then quickly go back to about 192. It did this for many miles. Eventually, I then crossed from the 101 to I5, it was dark by this time and it was about 60 miles of nothing. Car temp started rising and rising, got to about 210 then 215 then 220, 225. I finally came up to a gas station and pulled in just as the temp hit 235. Parked and opened the hood. The reservoir cap had actually blown off and there was fluid everywhere except for in the reservoir. At this point it's about 8pm and I don't have much options. I filled the reservoir back up and make it to I5 and the bottom of the grapevine, it was short maybe 1/4 of a liter. I headed up the grapevine with the car hovering around 190 degrees but it started climbing after a few miles. At 220 I pulled over and let it cool down. I started up again and ended up in first gear at idle on the shoulder of I5 and cussing myself out... Car was around 215 to 220 almost the entire way up. When I finally got to the top and started down the other side, the car did cool down but wouldn't go below about 185. This was with ambient air around 65 degrees and basically coasting downhill for miles. In the past the temp gauge would have gone to the cold point but it wouldn't budge below 185 now.

I made it back to the hotel and the next day contacted a shop close by to have them take a look. He checked it today and called me and suggested he thought the head gasket might be blown. I talked to my usual mechanic in the Bay Area. He said if the head gasket was blown that I would likely see it through the reservoir because it would bubble a lot. I don't have those issues that I can see. I haven't seen any evidence of water in the oil (just changed it two weeks ago) and never seen any steam coming out of the tail pipe. Now, it could have blown while coming up the I5 but I was careful to keep the temps below 230 and nothing higher so not sure.

Aside from the obvious of being stupid for tempting fate twice by driving the car down here a second time.... I'm down to the following theories...

1. My Thermostat is sticking in the closed position. I base that on the 70 miles of driving with the car holding steady at 167 at freeway speeds but then getting into stop and go where it started to climb and then had nothing but trouble thereafter. I am thinking that when I slowed down, since the car was running cool, the Thermostat shut and then got stuck and wouldn't open thereafter.

2. Air pocket somewhere in the Engine that hasn't been bled. This is is very likely, with all of the fluid I've had to add, I probably have not given enough time to bleed that air out. This could explain why I'm getting so much pressure when I open the reservoir and the fluid runs back into it.

3. Radiator fan isn't running. When I've opened the hood, I have noticed that the fan on the passenger side is running but I haven't seen the one on the drivers side ever run. I figured the passenger side is for the engine and the drivers side is for the AC but I could be wrong. This might be an element but the car still runs hot at highway speeds so I don't think it's the only problem.

So, car as at the shop, I'm at the hotel and I'm not certain what my next move is. I am considering the following:

1. Replace thermostat (shop quoted $300 parts and labor).

2. Ask the shop to bleed radiator and replace all fluid.

3. Check both fans to ensure they are running.

4. Attempt to drive home and see how she does. I am hopeful I will make it back like I did last week but I'm leery of driving at night with these known issues.

The shop is not a diesel specific shop by the way but the guy said he knows someone who they might refer me to.

Thoughts???

The thermostat and flange needs replacing now no matter what other problems you have. Even with oe parts I don't see that costing 300. Call a local dealer and see what they want. The big fan hasn't run in some time. A few more miles home shouldn't do anything it hasn't already. The head gasket needs to be looked at with a definitive test. Any shop should have the test kit. There is no guessing here. Either the coolant has exhaust gasses in it or not. The bleeding of the cooling system should be part of the tstat job.

Diesel produces not much heat normally! It is because of efficiency of engine, if oil is not too thick! I have suggestion about bad injection timing! If timing is too early, it is possible too much heat from engine! I have had this problem. In winter time engine was warming up very quickly. After TB change this disappeared! You should check timing with OBD-II. Possibly disconnecting battery for 10 minutes will clear computer memory and errors if any. Then timing will go to default values for number of restarts. Possibly timing is ok, but fuel consumption to high? If pump is injecting too much fuel, possible heat buildup.
Possibly restricted CAT converter! Or DPF, if equipped...
Air filter not plugged?

It is worth to try drive with MAF sensor disconnected near air filter for short time, possibly in limp mode. What changes? After that - with coolant temp. sensor disconnected ( fuel consumption would rise). Sensors should be toutched with engine shut off. After needs ECU errors clearing. Dual temp. sensor checking - from instr. panel and from engine module temp. should be the same after sitting during night, with OBD-II. One part of sensor goes to instr. gauge, second to engine ECU.