Engine overheating and No heat inside the car?

I drive a '00 Jetta. On my drive home from work one cold February night, I looked at the dash to learn the coolant was overheating. Many people would think the temperature gauge translates to the engine overheating, but that's not neccessarily the case. I cranked the heat inside the car to hopefully remedy the situation, only to find cold air coming from the vents. Now I'm no mechanic, but I know how to handle a wrench, and hoping it was the cheapest (and easiest) thing that could possibly be causing the problem....thermostat. Took out the thermostat out of the car and submerged it in a pot of hot water..this works just fine (water boils

212 F). My thermostat is supposed to open in the neighborhood of 180 (it'll say right on it) and it was fully open before the water was to a boil, so I was confident that wasn't the problem. My wallet began to whimper. I can't drive my kid around in the cold, so I'm forced to immediately take it to a shop. Told them my story...they vacuumed out the entire cooling system and filled it to the brim so there were to air pockets. They drove it for about 10 minutes...had heat in the car for about 5. Same symptoms came back. Let it cool back at the shop...discover air pockets have formed and the only explanation is that combustion gas (when and where the gasoline is actually ignited and the explosions occur) which, infortunately means the head gasket has failed (or blown, as it's known).
Reply to
illmanilla
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We have a Jetta. Sorry to disagree but you should complain. Our other car is a 98 Saturn with over 150,000, no engine problems and little money spent on repairs. Previous cars have been about the same, even our Neon went over 125,000 with no major problems except the dumb fan always stopped every few years due to rust (just cleaned it out). Got rid of it when I hit a large chunk of ice and destroyed the oil pan. Car drove over 17 miles from work to home, red light came on just as I got home. Next day drove it onto a flatbed, no trouble.

I'm not complaining either BUT, these cars are rough on the wallet. They are however great in crashes!!!

Good luck, Dermott

Reply to
Diarmud387

I bet if you replaced the water pump first then rechecked you wouldn't have needed a headgasket. Unless you continued to drive the car after the no heat/overheat issue started. If you were the first owner then it would have all been covered under warranty!

Reply to
Woodchuck

Woodchuck, On another post you mentioned that the MK IV has a very good reputation with head gaskets. Do you think in this case below that it was a water pump not the gasket? I hate these new 'stretch' style head bolts and usually replace them with 'raceware' studs. Would like to hear your opinion on this and head gaskets in general and anything that the user can do to keep them from leaking. thanks

Reply to
David

Yes, I do believe that it was only in need of the water pump. We see it all the time that owners drive the cars to the shop overheating and no coolant left in the block. We even seen the plastic coolant outlets melted off the heads and once the water pump and necks are replaced no head gasket is needed. VW started using the multi-layer metal type head gaskets around 94 or so along with Audi. I think this type of gasket out lasts the old composite 10,000 to one or more. After all if it doesn't fail then warranty costs are lower for VW. When stretch bolts were first used I couldn't understand how a bolt could live with being torqued to "x" ft/lbs and then another 1/4 or 1/2 turn. The thinking the stretch bolt is one it's torqued to spec and then given that 1/4 or 1/2 turn it's at it's max holding power. all other car/truck & marine companies are using stretch bolts. At our shop we have an employee with a 83 Rabbit which has a Corrado engine modified which was dynoed at 250hp. This engine has a aftermarket belt driven roots supercharger with 20+lbs of boost and the engine uses stock VW headbolts and hasn't been apart in 2 years. Keeping the 5 speed together is another story.

Reply to
Woodchuck

Thanks for the answer. ~d

Reply to
David

reputation with

The most important thing you can do to keep the head gasket from leaking is shut the engine down if the coolant temperature guage goes high. Especially if the heater is also blowing cold.

Yes, sometimes the guage is wrong and the engine isn't actually overheating, but yours probably was. And if you had stopped immediately when you saw the high engine temp and no heat, your gasket might have survived. When the guage says it's overheating, it's best to stop and believe the guage until you have actually verified that the guage is wrong.

A common failure mode with VW water pumps is that the impeller/rotor separates from the shaft. So there's not necessarily leakage from the pump, and there's not any bearing noise or other outward signs, but it just doesn't pump the coolant any more. No movement in the coolant means:

  • no hot air from the heater (big clue)
  • very little coolant flow through the engine, resulting in very high temperature showing on the guage (another big clue)
  • If you keep driving it, the water can boil away and when there's nothing in the coolant passage that the guage sender is in, engine temp as indicated by the guage will fall quickly to near air temperature.

As for head bolts, I've had very few problems with the stock bolts, even on the diesels. As long as the proper procedures (from the latest Bentley edition that applies to the engine) are followed installing them, the stock bolts seem to be more than adequate.

Since I mentioned diesels, the old 1.6D's and 1.6TD's are harder on the bolts, and they have different procedures for installation and tightening, including an additional tightening at 1,000 miles after installation. That additional tightening step is critical to reliable operation, and expect problems if you skip it on the diesel engine. The

1,000 mile check/re-tighten step is a diesel only thing, though, don't worry about it on gas engines.

My usual maintenance schedule is to replace the timing belt, seals (cam, intermediate shaft and crank seals), accessory belts, water pump and all coolant hoses every 60,000 miles. I also replace the passenger side engine mount on the A1 cars (Pre-1984 cars plus Scirocco and Cabriolet through 1992). On a gas engine (8 valve only), with inspection of the timing belt to verify that it's not stretched or damaged, you can stretch that interval out to about 90,000 miles without much risk. Just check the belt every oil change or two, and if it shows signs of excessive wear or stretching, replace it.

And water pumps are one of only 3 or 4 parts that I actually go to a $tealership to buy. I've never had really good luck with rebuilt water pumps (on any car), so I always get new ones. But with the VW's, I've had enough problems with "new" aftermarket pumps that it's no longer a risk I want to deal with.

-- Racer X

1984 VW Jetta Diesel GT 1992 Mazda Miata (looks OK considering it's been hit by an 18 wheeler) 1994 Caravan (OK, maybe it's a keeper, but I still want a VW Caddy) 1995 Ford Escort (may it rest in pieces) 1983 VW Rabbit GTI (ITB racer) 1988 Mazda RX-7 (maybe for sale, make offer) 1992 GMC Topkick (portable garage for racecar[s])
Reply to
racer_x

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