Engine overheating from low fuel

My 2000 Chevy Tahoe fuel guage has not been working for weeks. Now my engine is overheating. I am told it might be the fuel pump. I do let the gas run very low before refilling. Can my engine overheat from a hot fuel pump?

No. it cannot. The fuel pump is located in the gas tank and has no relationship the the engine overheating. However, running out of fuel could fry to fuel pump, so start filling it more often.

Have you checked your coolant level?

Yes. There is pink fluid in the white plastic jug. So is the gas guage issue separate? thanks for your help.

Yes, the fact that you run your gas low is seperate from the overheating problem. Keep doing it and you may cause another problem, but it’s not related to the overheating.

I’d suggest you get the vehicle to a shop ASAP, before the overheating creates permanant engine damage. It’ll probably be just a $15 thermostat, but it needs correcting.

Thanks. I have been crying since yesterday over this and it might cost $15 dollars! You just made my day. The guy at the garage told me I might need a new fuel pump and the cost was a few hundred dollars. He said he couldn’t take me until Monday thank God! I appreciate your help! I’ll fill up sooner from now on. Have a great weekend.

Um…please understand that while the overheating is unrelated, needs correcting, and may be only an inexpensive thermostat, you may have already caused the fuel pump problem.

In other words, you may have two problems. I can’t tell from here.

Please don’t cry. Repairs are only a normal part of car ownership. It is, after all, only a machine.

Its starts up and runs for a bit before overheating. The garage that told me it was the fuel pump spoke to me on the phone only and asked I drop it off on Monday at 7AM. I am hoping the thermostat is the issue. That would be great news.

Beside the coolant overflow tank, have you removed the radiator cap (with the engine cold!) and checked the coolant level in the radiator?

The gas gauge in my 2000 Blazer stopped working 2 years ago. I keep track of my mileage and mpg and try not to let the fuel tank go below 3 or 4 gallons. So far the fuel pump is holding up. Unfortunately the fuel pump is an expensive repair.

Good luck,

Ed B.

You’ve brought up 3 problems-

  1. fuel gauge doesn’t work - unrelated to fuel pump, but a reason to keep the tank full. Get it fixed or you might be stranded in a bad place some day.
  2. fuel pump - nothing you’ve described is related to a fuel pump problem. A fuel pump problem would prevent the Tahoe from running, not cause it to overheat. I would not trust a mechanic who said a bad fuel pump would cause the truck to overheat.
  3. overheating - This is the immediate problem, could be a simple as a thermostat, but who knows. Also, the part may be $15, but it will cost more to replace it. Like other said, you need to check the radiator (cold engine only!), add water if it’s not full before you drive it to a mechanic.

If you need to find a mechanic use the car talk mechanic finder: http://www.cartalk.com/content/mechx/find.html

I’m no chemistry major, but for some reason, a lean burning mixture leads to high combustion temperature. So low fuel can possibly lead to overheating.

Cars stop running at that point.

On a lot of American made vehicles, the fuel gauge in the instrument panel has a voltage regulator that also feeds the temperature gauge. It is possible that the voltage regulator is defective and causing the temp gauge to read high. Try to find out if your engine is actually overtemperaturing. One way to tell is if you are getting steam blowing off into the reservoir. Another is to use a infrared temperature tool to measure the head temperatures and the intake manifold temperature near the thermostat.

Hope that helps.

Would the voltage regulator be very expensive? I took the car to Chevy dealer here because Advanced Auto Parts said they didn’t carry the part and I would have to go to the dealer. He wanted $932 to replace a fuel sensor. $570 to replace the water pump. $163 to replace the thermostat. $1665! I don’t think its the pump because it fluctuates between working and not working. The 932 was to fix my broken gas guage. I am not going to fix that. To be safe, I took my time stopping every few to let the engine temp guage drop before continuing and called Napa. Napa told me to have the place next door install the thermostat and water outlet assembly which they said I could buy for $27.39. Out the door parts and labor was $91.41 I hope this solves my problem. Temp read slightly below half way on the ride home. I don’t know what temp level is normal.

As others have mentioned, you have two problems. Your fuel pump failed and needed to be replaced. This may have been caused in part by your habit of running your gas tank so low before you refill it, but will not make the car overheat. The sensor that registers how much fuel you have in the tank is located in the gas tank, along with the fuel pump. If it stopped working after the fuel pump repair, it may be the mechanic damaged it or simply forgot to reconnect an electrical connector. If it hasn’t worked since before the fuel pump went out, hopefully the mechanic checked it since he had to pull the fuel tank off the car anyway to replace the pump. If the problem is indeed the fuel gauge and not the sender in the tank or wiring, the cheapest and easiest fix would probably be to get an instrument cluster from a same or similar-model vehicle from a junkyard and have it installed. I’m not sure the voltage regulator on these is even replaceable, if it is even your problem.

If you drive your car when it is overheating, you will soon have a much more expensive repair–an engine rebuild or replacement. You are wise to stop and let it cool as you are doing, but it’s still putting a strain on the engine.

I’d suggest taking it to a good independent mechanic or shop and NOT the dealer. A dealer is not necessary for these types of repairs and a dealer will charge you hundreds of dollars more and not necessarily do any better of a job. Instead of throwing more money at it, I’d have the shop do some diagnostics. (with the exception of the thermostat you’re having replaced—that’s a good place to start when a car is overheating) I hope it fixed your problem. Good luck.

Nothing she has said indicates she has a bad fuel pump. That was the over the phone diagnosis of the “mechanic”.

Do not mistake a $15 part for a $15 repair. I’m pretty sure that the labor required to replace this thermostat is … well, don’t cry, but it might not be cheap.

OP could have a problem with her WATER PUMP! She needs a proper diagnosis by a competent mewchanic; with luck it will be only the thermostat.

Let’s clear the air. You have only two known problems: engine temperature indication and faulty fuel level indication. That’s it. That’s all. Everything else is just conjecture.
These two symptoms are all you tell your mechanic. Leave the conjecture at home.
I hope that that was miscommunication between you and the shop, by telephone. Any mechanic knows that actual overheating is NOT caused by the amount of gas in the tank. Your fuel pump is fine.
What the shop may have meant was the two dash gauge indications (the indications, not the actual engine or fuel pump) have something ELECTRICAL in common. This would be correct. They could.
The dealer was trying to take you for a ride. Hopefully, this independent shop has scruples. If you have any questions in your dealings with this shop, let us know.

This [the regulator] was true in the 70’s, and maybe the 80’s. It is not true for the 2000 Tahoe.