1500 dollars later, Daria's minivan is still overheating. What's going on?

Dear Car Talk

Dear Car Talk | May 01, 2008

Dear Tom and Ray:

I'm going to get right to the point here. I just spent $1,500 on the following repairs for my 1999 Pontiac Montana minivan. It was overheating big-time and losing coolant. Here is the list of the stuff they took four days to replace:

Lower intake manifold gasket set
Water pump
Thermostat and gasket
Serpentine belt
Oil change
Injector seals
Fuel filter
Air filter
Plugs and wires.

Well, I had it back for a grand total of 10 minutes, and guess what? It overheated again. By the way, they said they tested the head gasket and there was no indication of that being the issue. If you have any ideas, I'd love to hear them, because I am ready to drive it off a cliff ... and I may or may not decide to jump out at the last second! Hope to hear from you soon. -- Daria.

RAY: Don't drive this car off a cliff, Daria. It wouldn't be fair to whatever weeds and strewn garbage it lands on.

TOM: We've got two ideas for you. One is to check the rear heater pipes. This van has an optional rear heating system, and over time the pipes that carry the coolant to the back of the vehicle tend to corrode. And then they leak. That could explain your loss of coolant and the resulting overheating.

RAY: The other possibility is that the manifold itself is cracked and is allowing coolant to get sucked into one of the cylinders. This vehicle uses a plastic intake manifold, which is prone to cracking. That would explain your symptoms, too.

TOM: And since a head-gasket test looks for hydrocarbons in the coolant rather than vice versa, neither of these failures would show up in a head-gasket test.

RAY: Now, some of the stuff these guys sold you has nothing to do with losing coolant. A new belt, a fuel filter, spark plugs and wires won't do anything to plug a coolant leak. But they'll probably argue that you needed that stuff anyway, and you may very well have needed it.

TOM: But since they didn't fix your primary problem, I think you're within your rights to go back and ask them to try again. I mean, it overheated again after 10 minutes! Even WE have a longer warranty than that.

RAY: Yeah. Ours is 20/20. Twenty minutes, or 20 miles from the shop.

TOM: And since they clearly mis-diagnosed the problem, they should provide the additional diagnosis and labor at no cost to you. If you need additional parts, you can even suggest that they give them to you at their cost.

RAY: In the meantime, be very careful not to run the car out of coolant or drive it while it's overheating. If you do, you could end up with a cracked head or cracked block. And then we WILL have to guard the cliffs near your house, Daria. Good luck.

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