Hey all, I want to do a compression test on my car, just to see what I get. I never did one before, so also want to try it. Well, my gauges are out of the car right now, as I am repairing them. All the instructions say to run the car until normal temp is reached. I have no gauge as a reference, so how long should I run the car? Until my electric fan comes on? (no belt fan here!) or should am I better putting this off until I reinstall my gauges? Thanks!

 

once warm air is comming out of your heater you should be warm enough to do a test ,IMO

 

Or, when your oil temp drops to 3bar at idle. That generally means the car is ready for action (hot).

Edit: err, scratch that... you wouldn't know if you didn't have gauges
I figure 15 minutes is good... Electric fans coming on is good too.

 

When t-stat opens,just feel hose for temp change.

 

thanks!!!

 

I wouldn't worry about getting it warm, at least at first. You're primarily looking for consistency. If you have a hole that is far off from the others (10-15%), there's time enough for a warm test.

Consistency, this also means to do them all the same - specifically, throttle plate wide open or closed. I prefer wide open because a closed throttle can yield lower #'s because there's less air moving in to get compressed.