Blown head gasket
Heel & Toe
Joined: Jan 2015
Posts: 16
Likes: 0
From: sloatsburg new york
i am a full time tech best way i use is a handy little tool, remove rad cap and the tool fits perfectly apply vacume the solution changes color dont remember the tools name its about 80 dollars if it is head gasket use fel pro 1010 best one yet for L98
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
What chazc4 is referring to is a test that gives you the amount of exhaust gases that are present in the coolant. That is about the best way to be positive if you have a blown gasket.
Next is to pull spark plugs and compare the electrode and the ceramic around the electrode. What your looking for is a spark plug that is extremely clean as compared to other plugs. From past experience, #7 and or #8 are the cylinders most common to experience a blown head gasket. This is because of the relationship of the coolant passage to the edge of the head gasket around the cylinder walls.
You will also be losing coolant without any visible leaks. You might also have excess moisture from the exhaust.
Next is to pull spark plugs and compare the electrode and the ceramic around the electrode. What your looking for is a spark plug that is extremely clean as compared to other plugs. From past experience, #7 and or #8 are the cylinders most common to experience a blown head gasket. This is because of the relationship of the coolant passage to the edge of the head gasket around the cylinder walls.
You will also be losing coolant without any visible leaks. You might also have excess moisture from the exhaust.
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
Last edited by don hall; Apr 29, 2015 at 11:24 PM.
Thread Starter
Drifting
Joined: Dec 2012
Posts: 1,504
Likes: 73
From: Georgetown TX
Can I unplug each fuel injector one at a time to see if that cylinder is firing or not. If it's not firing I should notice no change at idle it idles very rough, just started doing it never has idled very smooth
Thread Starter
Drifting
Joined: Dec 2012
Posts: 1,504
Likes: 73
From: Georgetown TX
today I called my corvette shop, just to see how much to replace head gasket. I was told about 3500.00 because on an L98 both gaskets need to be replaced at the same time. I really don't believe that. I could buy new engine for that price
anyone know of shop in Austin area that they trust just incase I need head gasket changed. for that matter any shop in Texas you trust. I would drive many miles to get a good job at a fair price.
anyone know of shop in Austin area that they trust just incase I need head gasket changed. for that matter any shop in Texas you trust. I would drive many miles to get a good job at a fair price.
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
Head gaskets are about $70-80 for the L98. Another 30-40 for the intake gaskets and another 20-30 for the plenum and runner gaskets. Do it right and replace the head bolts with ARP and add another $100. $15.00 for a tube of the Right Stuff sealant and a thread sealant for head bolts. And then another $30 for coolant plus another $45.00 for oil and filter. PB Blaster or other penetrating fluid and never seize. Those are your basic costs. This could be done in a long weekend. Get the help of someone that has done this before and tackle it. You will need torque wrench,metric sockets and open ends plus torx.
If the car has not over heated, the heads are probably good and would not have to be machined.
If you do this, just remember to do this without exception.....label every bolt, nut, wire, hose and bracket. Draw pictures or take photos so you know how to put it back together. One of the reasons is that the bolts to the runners are different lengths. Take a piece of cardboard and punch holes in it and insert the push rods into the holes so it matches the exact position they came from the heads. Then put your rocker arms in the same sequence.
If the car has not over heated, the heads are probably good and would not have to be machined.
If you do this, just remember to do this without exception.....label every bolt, nut, wire, hose and bracket. Draw pictures or take photos so you know how to put it back together. One of the reasons is that the bolts to the runners are different lengths. Take a piece of cardboard and punch holes in it and insert the push rods into the holes so it matches the exact position they came from the heads. Then put your rocker arms in the same sequence.
Thread Starter
Drifting
Joined: Dec 2012
Posts: 1,504
Likes: 73
From: Georgetown TX
would love to do it myself, but the truth is I have no confidence to do it my self. I have a garage, tools and FSM, but if it did not run after doing the work, I would be in big trouble because I would not know where to go from there I love working on my car, but this seems like a little too big of job for just me. Don't know anyone in the Austin/Georgetown area to help me.. Even offered to pay someone to help me, but no one responded to my offer at that time. Did get an offer later from nice person at Ft Hood later, but already had paid to have work done
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Melting Slicks
Joined: Jun 1999
Posts: 2,931
Likes: 127
From: Ashland Alabama
Head jobs on an l98 are VERY easy. If you don't have to touch the valves and are just replacing the gaskets its a no brainer. Nice big bolts to deal with mostly and nothing to adjust.
The key is to make sure the heads flat after taking off the car. Use a straight edge will work. I usually have them resurfaced if aluminum but you can make sure they are straight with a straight edge ruler or such.
The key is to make sure the heads flat after taking off the car. Use a straight edge will work. I usually have them resurfaced if aluminum but you can make sure they are straight with a straight edge ruler or such.
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
The hardest part is dropping the distributor back in and adjusting the valves. I have a good write up on the valves and dropping the distributor back in is not too difficult. To make things easier, you pull the plugs so the motor will turn easy. Take a 5/8 (six point) socket and turn the crank to line up the timing marks (as you are getting compression on #1 cylinder). Then pull off the distributor cap. Take some masking tape and put it on your windshield and show the direction the rotor is pointing. Draw a picture or take a picture to help. Replace the head gaskets. When dropping the distributor back in, turn the rotor anti-clockwise about 1/8 of a turn. As you drop in the distributor the gear will engage and turn the rotor clockwise to about where you want it. Just don't rotate the crank until you put the distributor back in. Try not to turn the distributor rotor while it is out. If you have to you can always take a long screwdriver and turn the oil pump shaft a little to get it to line up with the base of the distributor.
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
You will have to at least loosen the hold down nut on the rockers and turn them to one side to remove the push rods. Keep the rods in the same order and position as they were in the heads (my note about the cardboard).
Melting Slicks
Joined: Aug 2008
Posts: 2,082
Likes: 50
From: Palmdale CA
You say; "I think I may have a blown Head Gasket" I say let's work on this first! And then if necessary move on to the Head Gasket fix, if necessary..
Head gasket repair's sound a bit over whelming, but are in fact quite easy..
Head gasket repair's sound a bit over whelming, but are in fact quite easy..
Last edited by desertmike1; Apr 30, 2015 at 06:45 PM.
Racer
Joined: Apr 2010
Posts: 372
Likes: 23
From: Harper Woods MI
I changed my own on my '84. Different motor sure, but still a SBC. I took lots of photos and printed them up when I reassembled everything. I also bagged and tagged everything. I took the heads to a local recommended machine shop and they checked them out.
Since the alternator, power steering pump and other front items were off, I changed my water pump too. I did find one issue when I did this. The harmonic balancer rubber mount was coming off. That was a bit much for me and I had a local shop take care of that. I also had the timing chain changed as well.
Finding a trusted shop is tough. It took me a while. You can tell its a great shop with all the hot rods and vintage muscle cars always out front.
If I can do it anyone can. It was a learning experience for me and I saved lot's of money in labor costs.
Since the alternator, power steering pump and other front items were off, I changed my water pump too. I did find one issue when I did this. The harmonic balancer rubber mount was coming off. That was a bit much for me and I had a local shop take care of that. I also had the timing chain changed as well.
Finding a trusted shop is tough. It took me a while. You can tell its a great shop with all the hot rods and vintage muscle cars always out front.
If I can do it anyone can. It was a learning experience for me and I saved lot's of money in labor costs.
Melting Slicks
Joined: Jan 2009
Posts: 3,482
Likes: 196
From: folsom california
Yeah, in those years, Detroit was caught in the cross fire of the metric revolution; everything on the engine is US standard, almost everything else on the car is metric; "English"? you don't even want to go there unless you're restoring old English cars; imagine telling the slacker at ACE hardware, "Eh mate, I be looking for something in a whitworth thread"