Bought A 94 LT5 With Known Problem - ZR-1 Net Registry Forums

billybaloneey · 08-14-2009

I bought a 94 LT5 engine with a known problem...an internal coolant leak. The engine has 149K on it, and it came out of VIN #424. It was posted on a major Internet auction site earlier this week. I was fortunate enough to be with driving distance...35 miles...I asked the seller if I could come and take a look at it and he said OK. The auction description said water was observed coming out from around the throttle body, so he put a new one on...that did not fix the problem so he put a new plenum on...that did not fix the problem...he reported coolant/steam coming out of both exhausts. At that point he shut it down and pulled the engine and replaced it with a crate motor he found...he is a GM part employee...so I guess he had some contacts. I saw the car...it was red...and there was a brand new LT5 engine...or one very, very, very clean LT5 in it.

Anyway, in addition to the engine being offered on the auction site, he told me it was listed locally for sale. After two offers he accepted, and I got it for significantly less that the auction asking price.

I picked it up today and started investigating. There is coolant in the oil pan and in the oil filter, so it appears coolant is throughout the engine. I could turn the crank without to much effort so the engine is not seized.

Any suggestions from you engine experts out there? Are typical internal coolant leaks on the LT5 due to gasket failures, block cracks, head cracks, etc? If there is a crack are they typically easy to spot? Are cracks prone to certain areas? Any suggested plan of attacks to locate the cause of the coolant leak?

For the price I got it at, even if it's cost prohibitive to fix or turn it into a stroker, I have a great source of parts...as mentioned there is a new plenum and throttle body on it...he gave the the old ones also. As can be seen from the pictures the engine is virtually complete...including a bell housing, clutch and flywheel. The only thing I've found missing so far is the dipstick and tube. He even included the engine lifting mounts.

MikeG · 08-14-2009

Clint, I just had new head gaskets put on my 91 (68+K) - white "fog" coming out both exhausts. The only way I know of to tell the condition would be to start with pulling the heads. Mine was on the right bank - #8. Left bank was OK. From some of the threads I've read, the back 2 cylinders are the one most prone to fail. Most of the info I got from the forum was under "head gasket", try that search and I know some other guys will be posting here soon.
It will be nice to have a "spare" motor handy - if there isn't too much wrong with the lower end. Hope it turns out to just be a minor problem.

phrogs · 08-14-2009

really im thinking head gasket.

Here the deal tear it down and see what you can find, you have the tools know and anything you need to put it back together we can help with that!..

Its really easy to do and it fun to see the inside of the engine at least it is for me I love this stuff!

billybaloneey · 08-17-2009

I don't have much spare time at the moment to begin investigating the internal reasons for coolant mixed in with the oil, but when I do, it looks like I'll have a big clean-up job ahead of me. Can anyone recommend a cleaner/solvent to get rid of the mix of coolant/oil that is sure to be everywhere? Or is the best approach to just take the major components and have them hot tanked?

phrogs · 08-17-2009

I have just used degreaser and cleaned it like that oh and lots of brake cleaner.

I don't have a hot tank and you wont hurt the plenum and cam covers powder coat if you get crazy cause its already done!

you could take it all apart and pay someone to hot tank it I guess I wouldn't. just a old tooth brush and some brake cleaner thats me

Jagdpanzer · 08-17-2009

You should tear this engine down as soon as you can. By the looks of it the biggest concern is corrosion on the bearing journals, timing chains, cam lobes, lifters, valve stems, and gear teeth caused by the coolant that found its way to the lube oil side. With this many miles if the previous owner(s) did not properly maintain the coolant you may find some pitting on the cylinder head deck in the cylinder liner sealing area and where the liners insert into the block. Then take it to a local shop and hot tank it.

09-14-2009

There are two dowel pins. Use a bigger rubber mallet.

Also just remove all your wiring harness and fuel rails. It'll just get int the way.

phrogs · 09-14-2009

Quote:

Originally Posted by Jeffvette

There are two dowel pins. Use a bigger rubber mallet.

Also just remove all your wiring harness and fuel rails. It'll just get int the way.

Don't tap it with the rubber mallet wack it with the mallet kinda under and up just like jeff said there are dowel pins stick up a little over a 1/4 of an inch over the base of the block.

You'll see give it a good wack don't be afraid you wont hurt it.

Hard to see in this picture but I love it

4DSZR1 · 09-14-2009

Great pictures, documenting your tear-down. I enjoy and appreciate you taking the time to post them.

I was wondering if anyone knows what the "1040" written on the front of the block means???

Rick

Polo-1 · 09-15-2009

1040's were know to leak water. These motors were built right after break time, on the line.

08-14-2009	#1
billybaloneey Join Date: May 2008 Location: Mauriceville, Texas Posts: 179	Bought A 94 LT5 With Known Problem I bought a 94 LT5 engine with a known problem...an internal coolant leak. The engine has 149K on it, and it came out of VIN #424. It was posted on a major Internet auction site earlier this week. I was fortunate enough to be with driving distance...35 miles...I asked the seller if I could come and take a look at it and he said OK. The auction description said water was observed coming out from around the throttle body, so he put a new one on...that did not fix the problem so he put a new plenum on...that did not fix the problem...he reported coolant/steam coming out of both exhausts. At that point he shut it down and pulled the engine and replaced it with a crate motor he found...he is a GM part employee...so I guess he had some contacts. I saw the car...it was red...and there was a brand new LT5 engine...or one very, very, very clean LT5 in it. Anyway, in addition to the engine being offered on the auction site, he told me it was listed locally for sale. After two offers he accepted, and I got it for significantly less that the auction asking price. I picked it up today and started investigating. There is coolant in the oil pan and in the oil filter, so it appears coolant is throughout the engine. I could turn the crank without to much effort so the engine is not seized. Any suggestions from you engine experts out there? Are typical internal coolant leaks on the LT5 due to gasket failures, block cracks, head cracks, etc? If there is a crack are they typically easy to spot? Are cracks prone to certain areas? Any suggested plan of attacks to locate the cause of the coolant leak? For the price I got it at, even if it's cost prohibitive to fix or turn it into a stroker, I have a great source of parts...as mentioned there is a new plenum and throttle body on it...he gave the the old ones also. As can be seen from the pictures the engine is virtually complete...including a bell housing, clutch and flywheel. The only thing I've found missing so far is the dipstick and tube. He even included the engine lifting mounts. __________________ Clint aka billybaloneey '94 - C4 ZR-1 #445 - Black/Black '05 - C6 silver/black 6sp '85 - C4 white/graphite (almost done) automatic '78 - C3 silver/black (a work in progress) automatic

08-14-2009	#2
MikeG Join Date: Aug 2007 Location: Sioux Falls, SD Posts: 77	Re: Bought A 94 LT5 With Known Problem Clint, I just had new head gaskets put on my 91 (68+K) - white "fog" coming out both exhausts. The only way I know of to tell the condition would be to start with pulling the heads. Mine was on the right bank - #8. Left bank was OK. From some of the threads I've read, the back 2 cylinders are the one most prone to fail. Most of the info I got from the forum was under "head gasket", try that search and I know some other guys will be posting here soon. It will be nice to have a "spare" motor handy - if there isn't too much wrong with the lower end. Hope it turns out to just be a minor problem. __________________ [FONT=Impact]MikeG[/FONT] [FONT=Impact]91 Turquoise Mettalic #135[/FONT] [FONT=Impact]1HOTZR1:cool: [/FONT]

08-14-2009	#3
phrogs Join Date: Jul 2004 Location: Kalamazoo MI Posts: 1,753	Re: Bought A 94 LT5 With Known Problem really im thinking head gasket. Here the deal tear it down and see what you can find, you have the tools know and anything you need to put it back together we can help with that!.. Its really easy to do and it fun to see the inside of the engine at least it is for me I love this stuff! __________________ JOHNNY P Currently own 90 ZR-1 #845 DRM 500 engine package 90 #226 Parts car Hit me up if you need anything.

08-17-2009	#5
phrogs Join Date: Jul 2004 Location: Kalamazoo MI Posts: 1,753	Re: Bought A 94 LT5 With Known Problem I have just used degreaser and cleaned it like that oh and lots of brake cleaner. I don't have a hot tank and you wont hurt the plenum and cam covers powder coat if you get crazy cause its already done! you could take it all apart and pay someone to hot tank it I guess I wouldn't. just a old tooth brush and some brake cleaner thats me __________________ JOHNNY P Currently own 90 ZR-1 #845 DRM 500 engine package 90 #226 Parts car Hit me up if you need anything.

08-17-2009	#6
Jagdpanzer Join Date: Apr 2007 Location: Northern VA Posts: 2,661	Re: Bought A 94 LT5 With Known Problem You should tear this engine down as soon as you can. By the looks of it the biggest concern is corrosion on the bearing journals, timing chains, cam lobes, lifters, valve stems, and gear teeth caused by the coolant that found its way to the lube oil side. With this many miles if the previous owner(s) did not properly maintain the coolant you may find some pitting on the cylinder head deck in the cylinder liner sealing area and where the liners insert into the block. Then take it to a local shop and hot tank it.

09-14-2009	#7
Jeffvette Guest Posts: n/a	Re: Bought A 94 LT5 With Known Problem There are two dowel pins. Use a bigger rubber mallet. Also just remove all your wiring harness and fuel rails. It'll just get int the way.

09-14-2009	#9
4DSZR1 Join Date: Dec 2005 Posts: 692	Re: Bought A 94 LT5 With Known Problem Great pictures, documenting your tear-down. I enjoy and appreciate you taking the time to post them. I was wondering if anyone knows what the "1040" written on the front of the block means??? Rick

09-15-2009	#10
Polo-1 Join Date: Sep 2005 Location: Washington Posts: 955	Re: Bought A 94 LT5 With Known Problem 1040's were know to leak water. These motors were built right after break time, on the line.