weird overheat issue.

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Nov 18, 2013 | 02:09 PM

#16

alloro

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From: 0,0,1

Quote:

Originally Posted by 77mud

Okay, if it was a blown head gasket, wouldn't i see some oil in the coolant or coolant in the oil? or possibly loosing water out the tail pipe?

Coolant mixes with oil when the intake gasket goes bad, not the head gasket. Yes you will get wisps of steam out the tailpipe with a blown head gasket, but that can often go unseen unless the problem is really bad.

Nov 18, 2013 | 02:14 PM

#17

alloro

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Quote:

Originally Posted by 77mud

when it runs hot its normally low RPM's. like Idling or going under 35 down the road. When it started to over heat I stepped on it tell approx 2-2500 RPM and it cooled right back off.

That could be because the system is air bound and the higher RPMs force extra circulation. It can also be due to broken impellers on the water pump, again increased RPMs increase flow. Lastly it could be the result of a bad radiator cooling fan clutch. The fan is only helpful from 0-35 MPH. After that the speed of the vehicle is forcing enough air through the radiator on it's own, making the fan irrelevant. If the overheating is most prevalent from 0-35 MPH then check the fan (engine off) to see if there is resistance when turning it, or if it freewheels.

Nov 18, 2013 | 02:44 PM

#18

70f100longbed

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Joined: Aug 2002

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From: Raleigh USA

+1 on the headgasket. Combustion gas is getting into the cooling system causing a airpocket. Lisle has a combustion gas leak detector that is a vial with blue liquid in it and you put it on the degas bottle and pull air through the liquid. If the liquid changes color then you have hydrocarbons in the coolant which means blown headgasket. It works very well and is foolproof.

Amazon.com: Lisle 75500 Combustion Leak Detector: Automotive

Nov 18, 2013 | 03:38 PM

#19

77mud

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Quote:

Originally Posted by alloro

Ive only seen it smoke or steam on cold start up, and about all vehicles do that (im talking below 40-50 degrees) but who knows.

Nov 18, 2013 | 03:45 PM

#20

77mud

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Thanks, guess ill have to look into it some more, looks like they'd be a PITA to change the head gasket in it. Ive done it on old ford engines such as my 429, BUT dont see me tackling this one if that is the case.

Nov 18, 2013 | 04:19 PM

#21

77mud

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Well fan seems okay. Not sure how much give it should have but id say if you give it a spin it only turns maybe 3 blades before stopping. I know when the one on my truck went out it would go around atleast twice before stopping