Full resivor Coolant low temp fluctuation

kendallrwynnApril 22, 2009

I recently started having trouble with my Ford ranger. I developed a small pin hole in the pipe running to my Intake manifold I patched it, and refilled the coolant. now my tempauature gage fluctuates about 10 minutes into the driveit will drop down to cold, then go up to hot, then drop to normal. then occasionally it will intermittentaly fluctuate from normal to half way to red then drops back down to normal.

Today while driving it heated up and stayed at the 3/4 mark so I let the truck cool for about 30 minutes, I then checked to resivor. it was almost completely full. I opened the radiator cap, and it was almost a gallon low on coolant.I refilled it, and it ran for about 20 minutes at normal.

I had it pressure checked 2 times 4 days ago, and it hold pressure steady. Can anyone give me any help? my mechanic cant find the problem.

Thank you much.

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It's possible that there's still air trapped in the block. When the engine is cold, remove the radiator cap and start the engine. As the engine warms, rev it up a bit while filling the radiator with coolant. Easier if you have a helper. When it's as full as you can get it, replace the cap before letting the engine return to idle. Also helps if you can park where the front of the vehicle is on an incline.

Could still have a leak at the cap or in the line between the radiator and the recovery tank that will allow coolant to be pushed out one way, but allow air to be sucked in the other.

Just a couple ideas fwiw.

    Bookmark   April 23, 2009 at 7:52PM
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