sudden temp warning

dieselmani · Oct 23, 2016

I drove today 2-3 hours (2006 VW Jetta TDI) and all of the sudden the temp warning came up. After looking under the hood I noticed that the coolant tank was practically empty. I checked the coolant level a few days back and the tank was filled as it should. I haven't noticed anything else like moisture, a leak, or steam coming out. What could be the reason for a sudden drop like that? I changed the alternator pulley about a week ago, b/c the old one was bad, but this shouldn't have anything to do with it. Any suggestions are greatly appreciated.

meerschm · Oct 24, 2016

Could be you pulled on a hose working on the pulley could be a leak in a hose, or where the hose connects to some other part.

or it could be an unrelated leak. if it helps, you can get a gizmo to pressurize the system and make leaks easier to identify.

keep in mind you want to end up with a mix of the proper coolant. (so if you top up with water, plan to drain, flush, and refill. might be time for that anyway.)

jettawreck · Oct 24, 2016

I believe it's not a high temp warning, unless your dash gauge was indicating very hot (perhaps not even then, never got one HOT) it's a low coolant warning.
As per previously mentioned, check to see if you dislodged a hose or connection and look for signs of escaped coolant.
When is the last time the TB and WP were changed?

Mad_Max · Oct 24, 2016

I do not think the alternator pulley has anything to do with it. My guess it is a coincidence.

I had a similar coolant issue:
http://forums.tdiclub.com/showthread.php?t=394030

In my case it was a flange gasket leak. But several people had a heater core hoses having a pin hole leaks.
Max

dieselmani · Oct 24, 2016

Thanks guys for the input. Indeed, it could be something that I did while changing the pulley. There is a metal silver tube which is right underneath the fuel filter. It has a valve or something like that on top with a black cap. When I changed the pulley I had to press very hard to get it loose and this metal tube definitely moved or bent a little from the ratchet that rested on the car body next to it. I attached a picture of the tube below. Thanks.

windows 7 screenshot

dieselmani · Oct 24, 2016

I'm at 76K and I never changed TB or WP. In fact, I changed only oil, filters, the battery and recently the pulley so far.

meerschm · Oct 24, 2016

dieselmani said:
Thanks guys for the input. Indeed, it could be something that I did while changing the pulley. There is a metal silver tube which is right underneath the fuel filter. It has a valve or something like that on top with a black cap. When I changed the pulley I had to press very hard to get it loose and this metal tube definitely moved or bent a little from the ratchet that rested on the car body next to it. I attached a picture of the tube below. Thanks.
windows 7 screenshot

That metal tube is full of R134a. part of your air conditioning system.

dieselmani · Oct 24, 2016

Thanks meerschm for clarifying that one.

jettawreck · Oct 24, 2016

dieselmani said:
I'm at 76K and I never changed TB or WP. In fact, I changed only oil, filters, the battery and recently the pulley so far.

The reason I asked if WP has been changed is that can be a source of coolant loss and often sort of difficult to notice as the coolant gets dispersed from the Tbelt and engine heat.
While you are not at the change interval for miles (yet) most don't recommend that many years on a TB.

dieselmani · Oct 24, 2016

Thanks guys for the input on my leak problem. Today I filled up the coolant tank and took her for a spin, but after an hour of driving the warning light came up again. A quick inspection under the hood confirmed that the tank was empty. I think I could even smell the fluid, because it's a distinctive smell, but no evident signs of leakage. I looked from the top only and also behind the engine block where the heater core sits as described by Mad Max. From the top I couldn't see anything wrong, except maybe a little moisture on the bottom plastic cover on the left side of the engine block while looking straight down past the alternator/fuel filter area. Isn't that the area at the bottom where the timing belt and water pump sit? If the water pump is shut, would there be leak? Thanks again.

jettawreck · Oct 25, 2016

WP leaks when the seal goes bad. Either the bearing has gotten play in it and messed up the seal or the leaking seal will destroy the bearing. When the WP seizes the TB gets sheared/broken.
Inspect carefully to know if the WP is leaking. If so, don't drive it until it gets replaced with full TB service.

meerschm · Oct 25, 2016

http://www.myturbodiesel.com/wiki/2005-2006-brm-engine-timing-belt-replacement-vw-jetta-tdi-part-1/

look here and other places for info on timing belt replacements.

the purpose is for you to understand where the water pump is.

If you get access under the car (on ramps or securely on jack stands) and remove the plastic cover (big almost flat one under the engine compartment), you should be able to get a better idea what is leaking.

water pump leak would probably come out the bottom of the timing belt cover.

Be careful under the car. don't want to get hurt.

dieselmani · Oct 25, 2016

I just got the plastic ramps from K-mart and want to inspect the car from below for leaks. Should I let the car run while on the ramps to see where the coolant is leaking? I thought it might be the best method to find the problem.

Macradiators.com · Oct 25, 2016

Well there is another possibility, like in my case , the head gasket or cylinder head.
When i go high revs while driving , pressure increases in my coolant circuit, hoses dilate and water level drops, i can hear the air in my hoses after turning engine off.

Practically i get pumped air in my coolant, coolant overflows from the expansion tank.
with water at 90degrees if i rev 2nd or 3rd gear for a few seconds it spits the water out

If i dont rev the engine at all i can drive for days without spitting water out.

meerschm · Oct 25, 2016

dieselmani said:
I just got the plastic ramps from K-mart and want to inspect the car from below for leaks. Should I let the car run while on the ramps to see where the coolant is leaking? I thought it might be the best method to find the problem.

I would start by driving up the ramp while it is warm, set the parking brake and put a chock behind the rear wheel. Take a look with it warm and engine off. use a good light to see better. (safer to look around without stuff moving. still be careful, the radiator fans can come on even with the engine off...)

do you have the right tools to take the bottom cover off?

if you cannot see anything, you can turn the car on and keep watching.

again, be careful not to get caught in the moving parts.

dieselmani · Oct 25, 2016

I turned the car into the shop. When I got on the K Mart Rhino ramps at my house I really got scared of how little room there is to maneuver to get all the way to the back, so I went to a tire shop to get the car on a proper lift. After lifting the car and looking from the back with the cover still on - they did not want to take it off b/c they only fix tires

- it looks like one of the hoses behind the engine is leaking. So I went to another shop where they will be able to take care of it.

meerschm · Oct 25, 2016

Good Plan.

BobnOH · Oct 25, 2016

Also check that the radiator doesn't have small leak, mine did, it was very hard to see.

GoFaster · Oct 25, 2016

I betcha it's the pair of hoses leading to the heater core.

Been there, done that.

dieselmani · Oct 25, 2016

yup, it was one of the heater core hoses. I'm out of $135, but glad that I did not attempt doing it myself. Couple of hours at the local shop and I'm back on the road.

dieselmani · Oct 25, 2016

While on the lift, I noticed a whole in the engine compartment plastic cover - the cover which protects all of the bottom. It's not a whole entirely, but sort of a flap about 3"X3", which is now open to the back, b/c I must have hit something on the road. The opening is to the right off of the center of the engine. I think I even remember it happening like a rock or chunk of asphalt, but don't know exactly how long ago. Is it possible that this caused the problem with the hose in the first place, for example some debris off of the road, while going at high speed, got in and damaged the hose. A new splash cover is like a 100 bucks, but maybe worth replacing since it protects all of the bottom.

meerschm · Oct 25, 2016

https://www.amazon.com/Polyken-Premium-Military-Grade-Duct/dp/B003ZFE6WU

I have a roll of something like this I bought 15 years ago, and used on the bottom cover where I cut it to put a hitch on my wagon.

works ok, and may be an acceptable alternative to a new bottom cover.

Just to patch it up.

dieselmani · Oct 25, 2016

I thought about it as well; I have this silver duct tape from home depot, but with all of the moisture doesn't it come off quickly? Or is this tape more resilient?

meerschm · Oct 25, 2016

the one I linked to is mil-spec, 100 mph tape,

but it still comes off after a couple years under the car.

I think the normal grey stuff would not last so long.

HD sells some stuff called gorilla tape for $10 or so.

not sure the gash in your cover is related to the leaking hoses.

if you are worried, you can replace the plastic cover, or by a hard replacement from dieselgeek or other vendor.

http://www.dieselgeek.com/Volkswagen_and_Audi_skid_plate_kits_s/1829.htm

jettawreck · Oct 25, 2016

You can't beat a Panzer Plate. Get one!

belome · Oct 27, 2016

My car hasn't had plastic plate underneath for at least 200k miles. Everyone claims doom and gloom if you don't have it on there, but I still have the original turbo and live in the rust belt.

dieselmani · Nov 3, 2016

I got on my plastic Rhino ramps today and took off the splash cover to patch it up. I used gorilla glue and tape from home depot and the result was satisfactory. However, after the bing bang underneath and the size of the opening which was about 5"X3" and the air cushions blown around the impact area I probably must consider myself lucky that nothing further happened. Thanks for the tips guys and I think I'll start saving for a panzer plate

sudden temp warning

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