4.3 mercruiser EFI running cold

gruube

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exMember
Joined
Sep 12, 2007
RO Number
28551
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7
I have a 2001 2760 regal commodore w/4.3 mercruise EFI alpha one gen II. I noticed the other day that my right engine was at 100 degrees and my left engine was at 170 degrees. Of course I did the Faria rap to no avail. I went ahead a replaced the t-stat with no change. I also swapped the temp sensor, also with no help. I measured the temp at all the exhaust manifolds, three were at 100-105 and one was at 130-135 degrees. Yes the hotter one was on the cold engine ( right manifold right engine). What should be the next thing that I check? Has anyone ran accross this before? I'm glad that I finally found this forum. Any help is greatly appreciated. Thank you ALIGIRL Fells Point MD.
 
First thing I would try is to swap the gauges. I just don't trust the Faria gauges anymore. Esp. if you have been doing the Faria rap. After a while the gauge just isn't any good any more.

You said you measured the temp at the manifolds, did you try measuring the temp at the thermostat housing?
 
after you bring both motors up to propper operating temp, try swapping the pick up wire to the sending unit to the other engine. if the problem follows to the other motor either the gauge is bad or the wiring/power supply to the gauge is bad.
 
I had this problem with a merc. The thermostat was stuck in the open position. A small rock was lodged in the opening.

Be careful about running too cool. This can cause problems also.
 
Friend had this problem with a single engined Volvo/305 combination. We went after the instrumentation and it turned out to be the thermostat. The OP says you changed it but new parts can be bad out of the box. If you remove it from a cold engine, it better be closed. If it's not, take it to a pot of boiling water and dangle it in the water from a piece of coat hanger or such. You should see it open smoothly to wide soon after immersion, and close smoothly to full shut just after you lift it out. Do this a number of times to make sure it operates consitently.
 
swaped faria gauge and the problem went to the other side. Thanks crew
 
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