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JOHN aka Eauto
JOHN aka Eauto, The Car Guy
Category: Chevy
Satisfied Customers: 16008
Experience:  ase tech
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I currently installed a Jasper Remanufactured 3.5L Inline 5

Customer Question

i currently installed a Jasper Remanufactured 3.5L Inline 5 cylinder engine into a 2005 Chevy Colorado Z71 due to Engine Oil Pressure falling to 2psi after 20 minutes of run time and when this was occurring the engine temperature would run to the red mark on the temperature hand. After installing the new engine including the jasper instal kit which included new belts hoses and thermostat and water pump the truck runs like a top and the engine has 40psi of oil pressure but the temperature hand is wanting to sit one line about midway is this common?
JA: How old is your oil pump? Has the check engine light come on?
Customer: Brand new oil pump with maybe an hour of run time on it and the check engine light isn't coming on. It was before i replaced the engine
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: Im a ASE Certified Master Mechanic i have my own personal shop I'm just looking for literature on this issue in the case the customer questions the temperature hand
JA: Anything else you think the mechanic should know?
Customer: i have seen several forums that talk about the Colorado having major complaints over the inaccuracy of the temperature hand
Submitted: 11 months ago.
Category: Chevy
Expert:  JOHN aka Eauto replied 11 months ago.

thats the normal zone have you verified coolant temp with a laser thermometer or with live data on a scan tool?

Customer: replied 11 months ago.
Using my Snap On Solus the trucks operating right at 198 degrees. The initial Complaint from the customer was the truck seemed to run hot at highway speeds and also when coming to stop light. When this occurred sometimes the engine oil light would come on and go off once RPM increased. Checked Engine Oil Pressure with wet gauge when running hot and it was below 4PSI. The customer went with a Jasper Reman 3.5 Engine and the oil pressure at idle now is 40psi and the scan tool shows engine temperature to be at 198 but the temperature hand wants to sit one notch above the halfway mark. i have found on many forums that customers have many complaints due to the Inaccuracy of the temperature hand. At the midway mark before the Engine was replaced my readings varied from 195-210 with the hand reading midway to the next notch. Is there a fix for the inaccuracy in gauge reading or should i recommend the customer let me instal a after market Engine Coolant Temperature gauge?
Expert:  JOHN aka Eauto replied 11 months ago.

thats the normal zone.. would a add on coolant temp gauge help? they even have them with digital readout...but that is the "normal zone"

Customer: replied 11 months ago.
Right honestly i am currently looking for some form of literature to give to the customer explaining that its normal for this particular vehicle to have the temperature hand reading above the halfway mark.
Expert:  JOHN aka Eauto replied 11 months ago.

hmm not sure if i can furnish that

Customer: replied 11 months ago.
Like I said i see plenty of chatter on Colorado Forums talking about 10-20 temperature reading changes and the hand reading roughly the same position on the gauge and i didn't know if there was a fix to make the gauge more accurate
Expert:  JOHN aka Eauto replied 11 months ago.

the only thing you can do is attempt to have the stepper motor replaced, or a external gauge..but a liitle above or below half is 100 percent the normal / safe zone