Roadmaster temp gauge fluctuates

TUBEHEAD

MEMBER
BUICK ROADMASTER

93 Buick Roadmaster, 5.7L, 140K miles. Car runs like a top, no leaks or noises. The temperature gauge on the dash will heat up to the normal 10 o'clock position and stop there for a couple minutes. Then it slowly climbs all the way (pegs somtimes) up over about a minute of driving. Then it immediately (3 or 4 seconds) goes back down to normal. It keeps doing this until the car is shut off. High speed, lo speed, or idling does not seem to have an effect. The car does not appear to be overheating, no boilovers, no sevice engine lights, nothing. I've driven like this for a couple thousand miles with no ill effects. Change the temp sensor in the head, radiator, fan, thermostat (even tried removing thermostat), flushed system; absolutely no effect. What's up?

3 Replies

MATHIASO

MECHANIC
1,209 POSTS

The indicator device or circuit is probably defective. Replaced sender in head, replaced gauge, computer if the infrared shows normal, check that and let us know.

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Sunday, February 4th, 2007 AT 9:42 AM

FAUXZAPPA

MEMBER
1 POST

I'm going nuts with the exact same problem on my 70k Roadmaster Wagon. I can see the fan kicks on, no loose fan clutch, replaced the thermostat and radiator cap and still keeps happening.

Has anyone else heard or better yet fixed this problem.

I'm really not sure its not overheating or if its the gauge wandering. No white smoke or loss of fluid, so I'm pretty sure its not a head gasket either.

I could change a handful of sensors but it looks like thats a shotgun approach.

Thanks for the help.

93 Roadmaster Estate LT1 70k original miles.

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Monday, September 24th, 2007 AT 10:43 PM

KEVIN VOSS

MEMBER
2 POSTS

The guy I bought my 1995 Buick Century told me that the temperature gauge has read very high the whole time he owned it and that the car has never overheated or cause any problems. Over time he decided to ignore it and just drive the car. I replaced the coolant temperature sensor and that made no difference. I was going to change the thermostat till I read how hard it is to do. I have bled the cooling system, no air came out at the bleeder, just coolant so I don't think that is the problem. I am wondering if the gauge is faulty, anyone else have this problem?

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Saturday, July 2nd, 2016 AT 7:15 AM