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When I Accelerate In Moderation I Can Cruise 90mph @ 199 Degrees, But When I Get With It (hard Acceleration) The Temperature Shoots Up To Sometimes 258 Degrees. After A Little While The Temperature Drops Back Down Around 199-208. Can Anyone Give Me Some Direction As To How To Correct This Or Is This Normal?

Note: Brand New Waterpump, Thermostat, "hollow Bolt" And Line Clean, Plugs And Wires New
 

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1999 White Diamond ETC
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258 seems too hot for my preference. I tried the WOT cycles in 2nd gear, prescribed in the Technical section, and achieved over 230. That was the last time I did that.

High RPMs will definitely raise temperature, but only steady high RPMs would achieve such high temperatures.

My usual range is 192-213. When I do a WOT it goes up by 1 or two, but always within that range, unless I keep the RPMs high.

It's an aluminum engine, I would not feel comfortable exposing it to anything above 230... that's my PERSONAL opinion... not law.
 

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258 degrees with WOT is not a good sign. Check the water pump drive belt for proper tention. If it is rusty and frozen at the pivot point then it may be slipping at WOT. If that checks out ok then I'd do a cylinder pressure test rule out head gaskets.
 

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No way you can get that hot that quickly, then cool back down. Basic thermodynamics... so, what would cause that? Perhaps air in the system, heating up right near the sensor. Perhaps a bad sensor... something along those lines, but the actual coolant (if it's filled as it should be), is not gettign to 250+ degrees...

Go through the bleeding procedure and see if that helps.
 

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ZO95STS said:
How do you do a cylider pressure check?
You use an adapter that screws into the plug hole with a shop air quick disconnect on the end of it. Screw it into the plug hole and attatch the shop air hose to it and pressurize the cylinder, being sure the piston is at TDC. Then watch for air bubbles in the surge tank and listen for air hissing at the tail pipe. Either will indicate a bad head gasket. Do this on each cylinder. Use a breaker bar on the crankshaft damper to rotate the engine to TDC for each cylinder being tested.
 

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Ranger said:
You use an adapter that screws into the plug hole with a shop air quick disconnect on the end of it. Screw it into the plug hole and attatch the shop air hose to it and pressurize the cylinder, being sure the piston is at TDC. Then watch for air bubbles in the surge tank and listen for air hissing at the tail pipe. Either will indicate a bad head gasket. Do this on each cylinder. Use a breaker bar on the crankshaft damper to rotate the engine to TDC for each cylinder being tested.
Just to clarify - the procedure you're describing is a cylinder leakdown test (which is appropriate for what you're trying to figure out) - I only mention this to try and ensure that it's not confused with a compression test (which is also a great way to establish the "health" of an engine).

Steve
 
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