81 head gasket - update: looks like the head gasket!
#1
Rennlist Member
Thread Starter
81 head gasket - update: looks like the head gasket!
So for the last year or so, I have had to add coolant to the expansion tank about once every 8-9 weeks. There is no leaks of coolant on the floor or around the engine. I get some white smoke, but in 2-3 minutes it's gone.
On Monday I topped up the coolant to the normal level (took about half a quart) and then went for a drive - no problems. Tuesday night I took it out again and after about 10 min, the car started running really bad. If I baby the throttle it runs so..so. If I gave it more, it sounded like I was in high gear at 20 mph, when I was in 1st. At higher rpm I had a terrible vibration. It sounded like a cylinder was dead. As I limped home the coolant light came on - uh..oh!
Got home checked the coolant level and the expansion tank is empty...ahhhh..no! Check the exhaust and I got wet stuff coming out.
Anyway, this weekend, I am going to remove the plugs and check compression, but I have a sinking feeling the 4.5L is done.
So, I think I have 2 options;
1) Try to rebuild the 4.5L - Here I already have the engine but I understand it is very costly to rebuild.
2) Get a 4.7L and rebuild it to replace the 4.5L - this option means I need a 4.7L engine to rebuild... or at least reseal.
Any thoughts or feedback would be appreciated.
NOTE: I have checked the oil and it is dark but not chocolate or discolored. There are 6000+ miles since the last oil change.
Cheers,
On Monday I topped up the coolant to the normal level (took about half a quart) and then went for a drive - no problems. Tuesday night I took it out again and after about 10 min, the car started running really bad. If I baby the throttle it runs so..so. If I gave it more, it sounded like I was in high gear at 20 mph, when I was in 1st. At higher rpm I had a terrible vibration. It sounded like a cylinder was dead. As I limped home the coolant light came on - uh..oh!
Got home checked the coolant level and the expansion tank is empty...ahhhh..no! Check the exhaust and I got wet stuff coming out.
Anyway, this weekend, I am going to remove the plugs and check compression, but I have a sinking feeling the 4.5L is done.
So, I think I have 2 options;
1) Try to rebuild the 4.5L - Here I already have the engine but I understand it is very costly to rebuild.
2) Get a 4.7L and rebuild it to replace the 4.5L - this option means I need a 4.7L engine to rebuild... or at least reseal.
Any thoughts or feedback would be appreciated.
NOTE: I have checked the oil and it is dark but not chocolate or discolored. There are 6000+ miles since the last oil change.
Cheers,
Last edited by Tom928; 12-01-2009 at 06:04 PM. Reason: change title
#2
used engines
I think I read that 928 International is haveing a half price sale on everything used during Dec.. I checked...now the 4.5 used motor is $1,500.00, and the 4.7 used is $2,000.00. If you can get one for half off... Only question is the shipping!
#4
check the oil, see if its all chocolate milk like. that way you dont waste you time pulling plugs. if its bad, some bearings could be toast. if its ok, which we all hope, then id go after a compression check.
#5
Rennlist Member
Thread Starter
I am considering this, but the shipping cost is the concern.
Also, IIRC isn't there a core charge?
Head gaskets do seem to be in season these days.
I looks like it is contagious!
I should add this to the original post. I did check the oil and it is dark (6000+ miles since change) but it is not chocolate or discolored. It does not feel gritty like water and it does not smell burnt.
Cheers,
Also, IIRC isn't there a core charge?
Originally Posted by LEADASS
I think I read that 928 International is haveing a half price sale on everything used during Dec.. I checked...now the 4.5 used motor is $1,500.00, and the 4.7 used is $2,000.00. If you can get one for half off... Only question is the shipping!
I looks like it is contagious!
Cheers,
#6
Drifting
You should be able to pull the heads, have them decked, and then reassemble with new head gaskets. You shouldn't need to get into the short block. You are probably looking at $500 in parts, $100 in cylinder head machining, and a full weekend of work to pull and reinstall the engine.
That, or find a good 4.7 and just swap it in and toss your 4.5. You can probably come up with one for $1000 shipped. I'd also put new head gaskets on that as well before you install it.
That, or find a good 4.7 and just swap it in and toss your 4.5. You can probably come up with one for $1000 shipped. I'd also put new head gaskets on that as well before you install it.
#7
Archive Gatekeeper
Rennlist Member
Rennlist Member
Core charge on an engine from 928Intl was $500 last year- I got the stroker engine last December (from a '91 GT) for $2250 plus $500. I wonder if Mark would credit me for my dead GTS block.....
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#8
Inventor
Rennlist Member
Rennlist Member
#9
Captain Obvious
Super User
Super User
If it’s only the head gasket, you don’t need to rebuild the engine, just replace the head gaskets. From what you descried, the gaskets are probably originals and failed because of age. A gasket set is a couple hundred $ and the rest is labour. If you can do your own wrenching, you can get it done for under $300 (this includes oil/filter, coolant and other tid bits).
#11
Racer
Hi Tom,
I feel your pain - I have just had exactly the same happen to my 86 euro.
I am about to pull the engine to do the gaskets and some other stuff while it's out. If your oil looks ok you should be ok with just doing the gaskets.
I feel your pain - I have just had exactly the same happen to my 86 euro.
I am about to pull the engine to do the gaskets and some other stuff while it's out. If your oil looks ok you should be ok with just doing the gaskets.
#12
Rennlist Member
Thread Starter
Sorry to take so long replying; however, I have not been able to get on the list for the last 2 days.
Anyway, I pulled the plugs and they don't look the best.
They have been in for 14 months, 16k miles.
There is black build-up (soft sotty, on the rim and the 5-8 bank has burnt insulators).
I will post pics if I can get them uploaded - I'm still having problems.
What do plugs look like that have been burning anti-freeze?
Haven't done the compression check as I can't find my trusty comp. gauge.
One thing I did find, the vacuum line "T" for the rear fuel regulators have cracked and when I went to move the line the end came out of the"T"!!!
The T" is split down 2 sides and looks cracked all the way around it. Looks like I'm replacing vacuum lines (or at least the "T"s) - again!
Also, at the rear of the drivers side head is a plate about 2" long with 2 bolts. I understand this blocks the coolant. There is alot of white "growth" on the top of the plate and some around the edges.
The aluminum down the side of the head, over the block and down the bellhousing is VERY clean. Looks like this plate has been leaking. I tried to loosen the bolts but they are in solid. Any ideas on how to get these loose?
Now, I would think that this would leave a pool of antifreeze if it were really leaking. The only thing I can think of (if this is my coolant leak) is that this is right above the exhaust and would drip onto the exhaust and be burned.
Does that sound possible or just wishful thinking?
Thanks for all the feedback.
I am still not convinced it is NOT a head gasket.
Anyway, I pulled the plugs and they don't look the best.
They have been in for 14 months, 16k miles.
There is black build-up (soft sotty, on the rim and the 5-8 bank has burnt insulators).
I will post pics if I can get them uploaded - I'm still having problems.
What do plugs look like that have been burning anti-freeze?
Haven't done the compression check as I can't find my trusty comp. gauge.
One thing I did find, the vacuum line "T" for the rear fuel regulators have cracked and when I went to move the line the end came out of the"T"!!!
The T" is split down 2 sides and looks cracked all the way around it. Looks like I'm replacing vacuum lines (or at least the "T"s) - again!
Also, at the rear of the drivers side head is a plate about 2" long with 2 bolts. I understand this blocks the coolant. There is alot of white "growth" on the top of the plate and some around the edges.
The aluminum down the side of the head, over the block and down the bellhousing is VERY clean. Looks like this plate has been leaking. I tried to loosen the bolts but they are in solid. Any ideas on how to get these loose?
Now, I would think that this would leave a pool of antifreeze if it were really leaking. The only thing I can think of (if this is my coolant leak) is that this is right above the exhaust and would drip onto the exhaust and be burned.
Does that sound possible or just wishful thinking?
Thanks for all the feedback.
I am still not convinced it is NOT a head gasket.
#13
Rennlist Member
You can have the coolant checked by your local garage. They should have a chemical testkit with colour indicators that will show if there is any carbon monoxide in the coolant, using a small sample of the coolant from the expansiontank (your car should be driveable first). If there is carbon monoxide in the coolant: the headgasket has leaked.
#14
Race Car
If water has entered the combustion chambers, the spark plugs will look extremely clean (no blackness at all) because the coolant effectively steam-cleans them.
Dan
'91 928GT S/C 475hp/460lb.ft
Dan
'91 928GT S/C 475hp/460lb.ft
#15
Rennlist Member
Thread Starter
Thanks, Ad0911, I will check into the test kit.
Dan - thanks, the plugs are not clean by any means. Both banks are black with the 1-4 bank having the insulators burnt.
On a side note, I am still not able to upload pics or even read the forum from home. I can read the forum from another network; however, I don't have access to the car pics from that network.
Cheers,
Originally Posted by Ad0911
You can have the coolant checked by your local garage. They should have a chemical test kit with colour indicators that will show if there is any carbon monoxide in the coolant, using a small sample of the coolant from the expansion tank (your car should be driveable first). If there is carbon monoxide in the coolant: the headgasket has leaked.
Dan - thanks, the plugs are not clean by any means. Both banks are black with the 1-4 bank having the insulators burnt.
Cheers,