how much trouble am i in?

[tmaxx411]

ive got a 97 talon base model with the 420a. it jumped timing, so i pulled the head to check for bent valves, found none. put it back together, and got it running. the first drive after that, it overheated horribly. found out it was due to a cracked thermostat housing. now it still overheats if im not moving, and there are tons of bubbles in the coolant system. did a compression test and found 90-75-75-75 from the pass side to drivers side. im guessing the head warped from the heat. im wondering if i could have done damage to the block too. it runs well, minus the overheating. it sounds like it has low compression when you start it though.. so.. my questions are how hard is it to warp a 420a block, and how likely is it that i cracked the block?

 

[92AWDHX40]

Doesnt sound good a head, im thinking pull the head check for warpage.

 

[nuclearr]

Soounds like you have a warped or cracked head take it to a machine shop and have them straigt edge the heads deck.

Did you by chance try to reuse the head gasket?

 

[tmaxx411]

new hg, new head bolts. so there's no chance of the block being messed up?

 

[prdsmracer03]

Bleed the cooling system before you jump on taking head of again, I'm not sure if the 420's have a valve to bleed with, but if not let the car run with coolant cap off while it bubbles up, the bubble should eventually go away (but keep adding water)if its not your head and the car should no longer over heat, also look for any leaks especially behind motor since those are the ones we don't see easily.

LJ

 

[tmaxx411]

ok, got a lot of work done today. figured out the main part of my overheating problems was my thermostat. pulled it and temps are much more stable. but it still overheats. did another compression test with a different tester, got 150, 100,110, 120 from pass to drivers side. also did a leak down test and came up with 15%, 35%, 35%, 20% from pass to drivers side. couldnt tell where the air was coming out either. it sounded like the spark plug tube the tester was in..

 

[turboglenn]

with compopression that low something is wrong, I wold say there's peobably some valves that were bent that you couldn't tell, sometimes you can't see them plainly but they wont' seal for combustion/comopression

also warped head could be possible too, but first put a cap full of motor oil in each cylinder and recheck compresion to make sure it's not the rings

 

[bryanwheat]

Did you actually pull the valves out of the head and check them, or just pull the head and look at them? IT's pretty apparent that you have a couple slightly bent valves or you didn't get the head gasket sealed.

 

[tmaxx411]

i want to blow this car up... did ANOTHER compression test, and it came out different again. this time, it was low, but in spec. i also tried putting oil in the cylinders to see what would happen. i got 130 120 140 140 without oil from the passenger side. i got 205 300+ 190 250 with oil. the 300+ one pegged the gauge, so idk what it actually read. does this mean the rings are shot?