Overheated badly now compression is low
#1
Overheated badly now compression is low
Today I was doing a series of datalogs and going for short drives. On my final datalog I noticed the smell of burning coolant. I looked down at the gauge cluster and notice that the coolant temp was pegged to the right. I was only 30 seconds away from my house so I decide to continue to my house before immediately shutting the engine off. When I got home I plugged in a OBDII scanner, the coolant temp was reading at 146. I cant believe mazda didn't put a simple check-gauges/overheating light on the gauge cluster. It probably would have saved my engine and many others. I just did a compression test, here are the results.
10 months ago pre-trubo compression was 160-170 psi on all 4.
Now
cylinder #1 135
cylinder #2 130
cylinder #3 135
cylinder #4 139
Is my engine trashed?
10 months ago pre-trubo compression was 160-170 psi on all 4.
Now
cylinder #1 135
cylinder #2 130
cylinder #3 135
cylinder #4 139
Is my engine trashed?
#3
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You may have lost ring tension and scuffed the pistons against the cylinder walls.
You don't need an idiot light because you would have kept driving it the rest of the way home anyway. It's your car, but I wouldn't have done it that way with mine.
You don't need an idiot light because you would have kept driving it the rest of the way home anyway. It's your car, but I wouldn't have done it that way with mine.
#5
I don't think the extra 30 seconds really mattered at that point. When I got back home their was already coolant on my garage so it must have been leaking before i even left. Chances are that it was overheated for quite some time. After I started the car back up to pull into my garage the AFRs were super lean and now i'm thinking that I cooked one or more of my new FF injectors . Going to pull the head and see how bad things are. If the piston rings are toast will I see obvious signs of scoring?
#13
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If the head is warped 0.020"...make sure you pull the cams and check for journal issues. With it that warped, you could have junked a cam journal and at that point you'd be way better off finding a new head. Dr.
#15
I've already taken the head to a machine shop and had them do a full rebuild. The warp was no where near 0.5mm and was small enough that just a resurface would have fixed it. I have all the stuff to put it back together but I have not had the time to do it. Plus it is currently over 100 degrees here in phoenix right now so i'm probably going to wait until it cools off a bit.
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