blown head gasket

[dhen]

Hi all,

I have no luck with this car. I just blew my head gasket today and need some advice, but some background first.

My car overheated twice because of a slow leak in the turbo coolant line last week. I fixed that and took it for a drive a few days ago. Good oil pressure and temperature, so I figured the problem was solved. Though I did see white smoke at one time, I diagnosed this as the engine running rich because it went away when I started it up again.

Today I had a hard time starting it, but it's been running rich, so I figured the plugs were fouled. Got it running and took it for a drive. Once it got running sounded fine and pulled great. The water temperature starting climbing and the oil pressure started dropping, so I turned around and went home. The oil pressure was 40 on the highway, but only 5 psi at idle when I got home. For a few seconds it made a scratchy sound on the highway, but this went away very quickly.

I figured I had another coolant problem, and the radiator was about half empty. I figured that the low oil pressure was due to the oil thinning out from the heat. The oil level was fine.

I let it cool down and tried to start it and couldn't. I took the spark plugs out and there was coolant in two of the cylinders. I did a compression check and it was all over the place 120, 100, 100, 130.

OK, so here is my question; do I need a new engine or just a new head gasket? The engine was rebuilt less than 300 miles ago. Is this something that should be covered under warranty, or is it something they'll say I did myself?

Thanks,

Darian

[boost_boy]

You need to get the head re-machined and get a new headgasket as well as head bolts (If you're not using ARP). I know this is a headache, but when there's a problem with the car, especially oil pressure, I would have shut it off and had it towed. Your oil pressure being low like that is suspect, but it could've been due to the blow headgasket. You've got a dilemma. If it were me, I'd pull the engine and go through it carefully because something isn't right.

[dhen]

Thanks for getting back to me. I was afraid of that. Do you think the bottom end is likely screwed as well?

Darian

[s13drifter88]

More than likely with low oil pres like that even if it hasnt spun a bearing yet theres most likely some heavy scoring on the bearings and life from there would be short lived. My advice would be a simple rebuild. Measure the crank journals. Rods journals should be 1.770" but I cant remember the main journals. If its within spec use standard bearings (I prefer ACL), if not then have it machined and use the proper oversized bearings (.010" removed, use .010 oversized bearings). Gently hone the cylinders, re-ring the pistons and regasket the motor with a freshly machined head. If youre going to use an MLS head gasket I recommend having the block surfaced with the head keeping tolerance to .001" and a surface finish of 50RA or smoother. Have the machine shop keep track of how much material was removed from the head AND block and order the gasket to accomodate for the thickness of the material removed I.E. .010" from the head and .010 from the block equals .020" or .5mm so use a .5mm thicker gasket to compensate. Hope this helps, good luck man.

[r34 gtr]

I once drove my CA18 300 miles after running it out of oil at 90mph on the interstate. It knocked like hell the whole way home, but after I changed the oil and let it sit for a week it ran fine. When I tore it down to rebuild it, the bearings had very little wear. Just sayin.

[s13drifter88]

hey not saying thatb strange things happen. i had chevrolet truck once that knocked when it wanted to. the most pronounced rod knock ive ever heard, nothing to be confused with a lifter or valve tap. sold it to my dad who drove it for 2 more years, knock on - knock off! finally spit a rod with no sign, sound or warning while me and him were going to visit family for thanksgiving one year. always made about 20psi of oil pressure at idle too. after many good, bad and lucky experiences I try to avoid catastrophe and bite the bullet on preventing further possible mechanical failures.

[dhen]

OK, I took the head off today and here are the pictures:



















Seems like I managed to avoid the worst of it. At least I didn't bend a rod.

Darian

[boost_boy]

OK, I took the head off today and here are the pictures:



















Seems like I managed to avoid the worst of it. At least I didn't bend a rod.

Darian

Judging from the pictures you posted, you definitely over-heated the engine, but I believe you have a more serious condition. Either your head bolts are done or your head is severely warped or both. I suggest getting new head bolts (if you don't have ARP units) and getting the head machined. The way this head was torqued, determined how this over-heating thing took it's toll and from the pics you provided, the seal was suspect from the start.

[dhen]

Thanks for the reply, Dee. Do you think the rod bearings are toast as well, or is that something that only a visual inspection can tell?

Thanks,

Darian

[boost_boy]

Thanks for the reply, Dee. Do you think the rod bearings are toast as well, or is that something that only a visual inspection can tell?

Thanks,

Darian

Drain oil, inspect oil (all good), close drain_c*** (love this phrase), change oil filter, get fresh headgasket, fresh bolts, clean surface of block really good, install new headgasket correctly, install newly refreshened head carefully, use proper method to secure new head bolts, add all the other garbage that makes the car run, add oil and "VOILA"....