I'm wondering if my original muffler on my 94 burb is causing my engine to over heat. I have good flow of cooant and water pump is turing it great. However I've noticed on stop and go traffic and idle, the temp goes up to 200-250 easily. BUt if I'm moving, the temp goes back down to 200. Turning off the AC only helps a little. I'm wondering it the old exhaust tubing and muffler are causing this. If so how much woulld new tubing cost on a 94 2500 4X4 Burb?.... I'm think flowmaster.

Possible, but replace the thermo clutch fan. My truck used to do the same thing, put the new one on, and doesn't get as bad. Also check that there isn't too many bugs in the condensor that could prohibit air flow.

What about the cat being plugged up?

A plugged up cat or muffler would make the engine heat up whether it was idleing or running down the road. Since his is only heating up sitting still and in slow traffic it should be an airflow problem such as faulty fan clutch or stopped up radiator fins. Fan shroud still in place?

Don't ignore a partially clogged radiator. For $10 or so you can get a backflush kit. Run some radiator cleaner in it for a few hours and then backflush it and replace your coolant/antifreeze. Something that needs to be done routinely anyway.

yes, a bad muffler can cause overheating. It happened to me, I had to replace my oldsmobile muffler (http://www.flowpowerexhaust.com/muffler~oldsmobile~flowmaster.html) with a new one. a clogged radiator or bad fuel pump should also be considered. try to check this parts. good luck, hope you'll fix it soon.

It could be any of the above or a combination of a few of them. First off I would flush the radiator and cooling system. Then have the thermostat replaced. If that doesn't help, then look for a different clutch fan. There are gazillions out there for a little of nothing. Then go for the cat. If the pipes and muffler are not loud or getting louder, then I would rule them out. I have never seen a muffler plug up before it rotted out. One last thing would be to have it checked with a scope or analyzer when it shows hot. It may be just the gauge or temp sensor acting up. Mine always climbs to around to 220 after I rebuilt the motor but it has never overheated and I have all new components.

Kevin

I am with Kevin, do the easy stuff first. Change the thermostat.

Also, I had a truck that did the same thing but ended up being the water pump. All outward appearances were normal, not even any seepage from the weep hole. I finally took the thing off and found out it was on it last leg. Just a thought.

damn was this thread dug up.....but for fun and an update....I replaced the thermostat and had a Magnaflow muffler put on. next year though I want dual exhaust on her. But I first have to address some oil leaks and some brakes.

Wow....I guess it was an old thread. I never noticed the date:lol: