Help with 91 Jetta leak and overheat, stranded at work!

[888]

Hey guys;

I've got a 91 Jetta 1.6 NA leaking fluid and a light telling me it's hot and a gauge telling me it's not.

I hadn't driven the Jetta since last Friday for various reasons. When I drove it home Friday, I noticed a smell like fresh mulch or maybe brake lining when I would stop and the air behind the car would catch up. Initially I thought it was somebody's flowerbed and then after a few more stops, I realized it was something in the car. It wasn't coming out of the dash vents and everything else (gauges and feel) was normal so I couldn't figure it out. When I got home, I checked the wheel temps for brake seizing and they were fine. I realized I threw a big piece of industrial insulation with rubber backing in the trunk at lunch and it was hot that day so I opened the trunk and was greeted with the smell of hot rubber. Close enough to the smell, I thought, and didn't think any more of it.

I forgot all about it until today when I drove to work. About halfway there, the smell came back. I kept checking gauges and sniffing the air vents and as I was coming around the last corner by work, the temp light started flashing. The temp guage was at normal position, right about the middle, it had run in the same place it always had all of the way to work at all the normal times, I ALWAYS watch the temp gauge. Never any more than half a needle above the middle at any time since I've owned it.

So I went another 50 yards to get some momentum and shut it off, coasted down the hill and into the parking lot at work. I was just opening the hood and someone pointed out the puddle under the car. It looks and smells like clean antifreeze dripping off the pass side floorboards just behind the engine. It apparently just started leaking because there is a short trail behind it. There is no sign of boiling coolant in the hoses, the oil on the dipstick is not mixed with water and the coolant level in the reservoir is good and unmixed. All the drive belts are there (new), no signs that anything was slipping. No leaks on the front of the block, can't see anything on the back of the block leading down to where the antifreeze is dripping.

So I gave it a few minutes to cool down and it restarted fine and purred at idle, I didn't drive it any.

The only things that have been done recently:
A new drive axle installed on the passenger side.
I unplugged the AC condenser harness plug and taped it off to see if it was causing the vibration that was bugging me. I did it last week sometime.
The water pump, timing belt, related seals, belts, and the fan thermoswitch were replaced about 1000 miles ago. The engine fan was NOT on when I stopped the car.

I did notice that my new diesel filter is leaking slightly at that round "manifold" that is held into the filter with that hairpin style clip and there is a little diesel on the fenderwall underneath it and on top of the filter. I think that has been happening for a while because there was a lot of debris under there that I cleaned up some time back and it was discolored under there. I guess I need to replace that manifold, it didn't come with the filter. Is that available aftermarket?

So what do you think? I can't think of anything back there that would leak antifreeze but it's an A2 and I don't know what's back there. I thought antifreeze eventually evaporates off of blacktop, this is staying put like oil.

What causes the temp light to come on when the gauge is reading fine? I know both work properly, the guage has mirrored the engine load exactly so I know it works and the temp light comes on at startup as it should.

So here I sit 40 miles from home, I need to make a decision whether to have it towed in or risk driving it. All opinions welcome.

thanks in advance!

[3Bunnys]

Have had the feeling...sitting at work running various trouble shooting scenarios through my mind..... OK.. some things I would LQQk for ..and remember I run the simplistic early 80's rabbits.
Verify you have coolant in reservoir....
With engine running do I have flow into reservoir from vent line on radiator .. I've had a plugged vent line (debris) cause problems..
Any obvious radiator fluid leaks.....
With engine running feel hoses and radiator....hot/cold/normal???Does heater produce heat???

Can't explain why idiot light and gauge are telling you different things!!!

Sticking thermostat (not opening) can result in hot engine and cold radiator, and radiator fan would not kick on because sensor is in radiator... I've heard about water pump failure where pulley/shaft are rotating but impeller isn't (but have not personally experienced this) if this were the case you probably would not see that stream of water from vent line connection to reservoir..
I've been known to limp home with heater on high to provide some engine cooling....probably wouldn't work if impeller isn't turning!!!


May your day get better...Richard

[888]

Thanks for the reply. I have also always run the Rabbits, this A2 is a first for me.

Got coolant in the reservior and it is at the proper level.

New water pump and thermostat 1000 miles ago with the timing belt change, they should be good.

Just found a partially broken wire to the sensor on top of the head mounted radiator hose housing, broken all of the way through now

Upper radiator hose was hot to the touch, didn't check the lower. Nothing boiling anywhere or steaming.

No fluid leaks besides the one at the very back of the engine compartment.

Guage was fine at all times.

the engine fan did not come on at any time, which is odd because the thermoswitch was replaced when the timing belt was done.

What sensor/condition does the temp light look at?

thanks

[3Bunnys]

My radiator fan rarely comes on, even on hot days like yesterday (mid 90's) or idling at intersections...

.....Diesels run cooler than gassers.. ever notice that the paint never "burns off" muffler and tailpipe like gasser!!!!

The fans run all the time when the A/C is on due to being wired into A/C controls ....

Check temp of radiator with hands in several places, it should be just as hot as upper and lower hoses,,, if not something is "going on"..

But I'm thinking you're lucky and that bad wire is your problem...

Richard

[888]

The wiring should be pretty easy, it's the leak that's bothering me.

Welp, it's 99% sure that it's the heater core leaking into the AC drain line. Starting to get the telltale windshield fog too.

Don't know what else it could be and it's the general consensus of a few VW guys I called.

The part they build the rest of the car around, can't wait to tear into that.

[libbybapa]

The light could flash not because the temp is too hot, but because the water level in the expansion tank got a little low from the leakage. It doesn't sound like it was overheating at all. Tough call on running it. 40 miles is a bit of a hike to be leaking. Pack a couple of extra gallons of coolant and a cell phone to call the towing company if you go for it.

Andrew

[888]

thanks Andrew, I called AAA and had them haul it to the house, getting a ride home with a coworker.

I'll probably bypass the heater core as a test and plan to tear the dash out and make the full repair later.

[CoolAirVw]

When your hot your hot, when your not your not!

[duffer]

If there's water on the floor, inside the car,
then it certainly sounds like the heater core
is leaking.

Replacing the heater core is a long and
tortuous job.

You also say that there's coolant leak at the
back of the engine.

There are three core plugs on the back of the
engine block. Perhaps you should check them
for any leakage.

Also, if you have a block heater in one of the
core plug holes, check that there's no leakage
there.

[Fatmobile]

Yep, if it's a coolant leak at the back of the engine it could be a block heater leak. Couldn't have been leaking too bad if the resevoir was full.
The flashing red temp light comes on when the coolant gets low, then latches on until you shut the engine off or disconnect the temp sensor wire. It also latches on during an overheat but uses the same sensor as the gause so the gauge would have to raise for the light to signal an overheat.
I wouldn't expect the rad fan to be on unless the temp was high (you said the heat gauge read normal) or the AC (ha) or defrost was turned on.
The broken wire might be for AC. It's for; if the engine is too hot the AC will shut off.

[888]

There's no external block heater on the car. I ran my hand all over the back of the engine block and there was no sign of leaking from the freeze plugs or the block. Carpet is not wet on the pass side floor or as far up as I can reach. The leak is just "appearing" beneath the firewall, there is no sign of it coming from the engine.

The mechanic said he thought that the core was just starting to go and it was leaking into the AC drain line which dumps out in that position under the car.

I'm getting the windshield fog and the smell and the leak so I'm thinking it's the core.

I have a much better uncracked dashboard, i need to install a better CD player, and I need to replace the fender antenna anyway so it might as well come apart.

I've taken out a number A1 dashes and rebuilt a mechanical VDO speedo/odo assembly so I'm thinking I can do this. Might take me a while but that's why I have vacation days, I guess.

Right now, I'm searching for a replacement electrical connector for the 2 pin coolant sensor. Mine's got a wire broken off flush with the connector body, need to replace that. Believe that one works the gauge. Always something I guess.

thanks for the input.

[hranko]

I know I'm late to the party, and it is a long shot, but there was a massive recall that affected pretty much all A2's that revolved around the heater core leaking and spewing molten coolant all over the passenger.

It is a long shot, but you might want to see if that car has ever had that recall performed. If not, this one might be on VW. Surely there isn't a statute of limitations on safety recalls, is there?

-Jeremy

[Vincent Waldon]

Right now, I'm searching for a replacement electrical connector for the 2 pin coolant sensor. Mine's got a wire broken off flush with the connector body, need to replace that. Believe that one works the gauge. Always something I guess.

.

Two comments:

- nope, that doesn't work the gauge, just the flashing red light when coolant is low... could be a big part of the symptoms you've described. As Fatmobile mentioned the circuit is a latch.. once it trips (like on a tight corner) it will stay flashing until you shut the car off, even if the fluid level returns to normal on a straightaway.

- the connectors that plug into the switchs on the injection pump that detect idle and WOT for the "upshift light" are the exact connector you need for the coolant sensor. On my car I disabled the upshift light the day I bought the car.. bingo.. two spare coolant sensor connectors(one of which is now in use). So, if you haven't deleted those switches yet and want to, or can find someone who did and kept the switches... you're good to go.

[bvolks]

It is a long shot, but you might want to see if that car has ever had that recall performed. If not, this one might be on VW. Surely there isn't a statute of limitations on safety recalls, is there?

-Jeremy

I just tried that this winter when I blew the heater core in my old Jetta and the local dealership wouldn't honor the recall. Replacing the heater core isn't that big of a deal. I've changed 4 so far and can easily do it in an afternoon. But I'm guessing if your car has A/C it might be a bit tougher.

[888]

I know I'm late to the party, and it is a long shot, but there was a massive recall that affected pretty much all A2's that revolved around the heater core leaking and spewing molten coolant all over the passenger.

It is a long shot, but you might want to see if that car has ever had that recall performed. If not, this one might be on VW. Surely there isn't a statute of limitations on safety recalls, is there?

-Jeremy

Hey Jeremy. Thanks for the advice. Hope the caddy is doing well.