1988 K2500 4x4 5.7L Head Gasket failed need help.

[Jeff M 1988 K2500 4x4 5.7L]

My engine overheated while towing about 2000 pound trailer. 130k miles on the truck. Have used Mobile 1 oil for last 100k miles. Oil always changed every 3k miles. Thought failure might be water pump or thermostat as high temp light went off while towing. I pulled over right away and let it cool down. Truck was down about two quarts of Antifreeze after it cooled down.

Once towed back at the shop, mechanic found a head gasket issue. White smoke coming out tail pipe and coolant bubbling and now discolored. 

This was my dad's truck so I want to keep it. Body in great shape. I would like to try the head gasket repair. Mechanic pushing for a crate engine replacement. Would like to keep costs to $2500 or less.

I see on the Forum that it's quite common for this failure near cylinders 3 and 5 in the head gasket.

Am I wrong to first see what the heads and block look like? 

My thee options are one replace head gasket and rebuild, two find a used engine with unknown issues, three replace with a rebuilt crate motor this option around 5K for this option. 

Mechanic says 8 out of 10 head gaskets issues end up with another engine either used or rebuilt. 

Last what info do I need to spec a used or rebuilt engine if I need to go that route.

Would like to here the pros and cons.

 

 

[richard wysong]

Welcome to the Forum! I would determine which cylinder is leaking before tear down then pull it apart If the gasket failure is not apparent then have the head checked by an automotive machine shop and check the cylinder wall for hair line crack, Is there coolant in the oil? Coolant on the bearings is not good so if it ran for any length of time with coolant in the crankcase a crate motor may be the way to go, That said it is a very easy engine to work on but 35 years of New England winters there"s bound to be corrosion issues with the exhaust bolts, oil pan and bolts etc. Is it a real 2500 (8 lug) or 6 lug? How many miles? Where in Mass? Intake gasket failure is a much more common failure that leaks coolant into the crank case. I had an 88 with typical problems for a 300k mile truck , Loved the truck. Check the price on a new GM engine before buying a rebuilt

Edited December 29, 2024 by richard wysong

[Jeff M 1988 K2500 4x4 5.7L]

Thanks Rich. 130k miles. Had the Manifolds changed out earlier this summer. So that part will come apart. It didn't see NE winters for 20 years. Dad was a snow bird. That's why frame and body in great shape. Plus he used to treat the frame from rusting. I think there is coolant mixed with the oil. As oil level is above the full line. I wouldn't think the coolant would mix with the oil? It looked all one color on the dip stick. Didn't see any water.  I'm in central Mass. This happened 10 Nov. Not easy to find a shop down here to do this kind of work anymore.

I saw one post, where a  member, did his tear down at 130k before he had an issue. I guess he made the right call. I'm very mechanical, but have not done a complete engine tear down. I do not have a covered garage to do the work. Where on engine is the engine number marked so I know what I may have to replace.

Why a GM new motor over say a Jasper or JEG motor rebuild? Curious. Thanks for the reply.

 

[KARNUT]

I bought a used truck years ago nice low miles. Did my usual fluid change and noticed no antifreeze in the radiator so I flushed it. A week later it started to get warm. Turns out I flushed out bars leak. I don’t know if it had a head gasket problem or cracked block. I added block sealer antifreeze. It worked. I was doing recycling at the time so it pulled some loads. I would give that a try before replacing an engine. It could buy some time.

[richard wysong]

Engine number is on the right front block deck just in front of the head but you shouldn't need that to get parts, Small block Chevy parts are fairly universal, Pull the oil drain plug and see how much coolant comes out before the oil. Does the oil look like chocolate milk? Brand new Targetmaster GM engines used to be much less expensive than a rebuilt but it has been years since I bought 1. They come with new oil pan and valve covers

[CamGTP]

Replace the headgaskets and send it.

 

Have a machine shop check the heads if you really want them to. They can hot tank them and deck them to make them fresh for a cost.

 

The last thought in my mind is to replace the engine. You didn't boil this thing down and headgasket failures are fairly common to the 350 engines. If you do the work yourself, I see no reason why it can't be done for under $600 in parts. Gasket kits are cheap, new head bolts are cheap, oil and coolant isn't that spendy. The only big cost would be if you send the heads out to be cleaned and checked.

 

Cleaning the block and preparing the work is easy. Lots of ways to do it and it just takes a little time.

[Jeff M 1988 K2500 4x4 5.7L]

Thanks everyone. Sending the truck to my mechanic in Maine to get repaired. Will let you all know the outcome.