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Temp increases/decreases but never in the RED

Hello,

89 Jeep wranlger 2.5L, 108,000miles

While operating my jeep (long distance where I can watch it closely) the temp will start to increase to 210 degrees, stay there a second then rapidly decreases to around 150 degrees then starts over (almost forming a pattern, up and down).

The heater stopped producing heat (everything else runs), so I took off the heater hoses and hooked a hose pipe to the core, flushed out some grime and dirt and not it flows without problem through the core.

But the problem is still there, and since I go long distances I want to find the solution.

To sum it up:

  1. goes back and forth from 150-210F
  2. flushed core
  3. going to change thermostat (could be stuck open? since normal was in the 200s when it was stable all these years)
  4. going to give the system a good flushing, the radiator is about 2 years old (but due to deployments didn't run on a regular basis

Does this process seem sound? and any added insight would be appreciated...

Reply to
PilotAH64
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Start by replacing the Thermostat. Two hundred and ten is probably what your smog engine was designed to run at. God Bless America, Bill O|||||||O mailto: snipped-for-privacy@billhughes.com

Reply to
L.W. (Bill) Hughes III

Sounds to me like you might have a sticky thermostat or air in the system, either could make it behave like that.

If it was mine I think I'd give it a good flushing, change the thermostat, and when it's refilled make sure all the air is out of the system... those Prestone Flush and Fill kits can be a big help with that as not only can you hook your hose directly to the system but the pressure helps eliminate air pockets. I used to have a terrible time with air pockets with my XJ after changing coolant until I put one of those kits on.

Jeff DeWitt

Reply to
Jeff DeWitt

I pull the head temperature sensor, fill to the opening, and then put it back in. I "never" get air pockets, knock on wood. Another trick I have is to pull one heater hose at the head, and pour some coolant in the hose so it fills the heater core. Heh, use a funnel for this step. It seems like a little extra work, but not nearly as much as trying to get that stubborn air/steam bubble out, once things have started to heat up.

Cheers,

Earle

Reply to
Earle Horton

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