2003 Corolla poor compression - Toyota Nation Forum : Toyota Car and Truck Forums

mmaseda · 11-25-2011, 10:45 AM

My 2003 Corolla runs very rough at idle. I also get 300, 302, and 303 codes. I did a compression test today. Results are:

C1=130
C2=60
C3=62
C4=110

Look like a blown head gasket. Is this something I could replace myself?

MasterTecInSTL · 11-25-2011, 11:10 AM

yeah it might be blown between 2 and 3. Try this to find out:

install #2 spark plug and check #3 compression then remove #2 spark plug and repeat. If #3 compression is higher with the #2 plug installed then this is most definitely the case.

The hardest thing about doing this job is messing with the timing chain. You might be able to find a way to hold the chain onto the cam sprockets and unbolt those from the cams - then do your gasket and bolt them back on and as long as the cams haven't rotated any it should bolt right back on.. but if you aren't careful trying to do it this way may end up becoming more work than it's worth!

mmaseda · 11-25-2011, 04:10 PM

Compression improves to 90 when I put the plug in so it confirms your thoughts that it’s a blown head gasket. Anyone know of a good mechanic in or around Tampa Florida that could replace the head gasket for me?

mmaseda · 12-04-2011, 07:53 AM

Since I can seem to find a good local mechanic I'm thinking about replacing the cylinder head gasket myself. In looking at the service manual it isn't clear if I will need to remove the timing chain cover. Can someone tell me if I need to?

Thanks

hardtopte72 · 12-04-2011, 10:36 PM

I am in Tampa Fl. That is a pretty big job. I could do it or see if one of my Toyota Tech buddies would take it on. You don't have to absolutely remove the timing cover but it is just so much easier to remove it personally. On a Corolla it is one of the easiest jobs. Just a bunch of 10mm bolts for the cover, the cams, and the headbolts.

Pm me for more details.

mmaseda · 12-30-2011, 10:33 PM

Just wanted to let everyone know that I was able to replace the head gasket myself. Wasn't difficult but took me several days. Car is working fine now. Thanks for everyones help.

MasterTecInSTL · 12-30-2011, 11:28 PM

Awesome! Thanks for touching base with us! Glad you figured it out!