I have a 91 Dakota, 2 wheel drive regular cab, body is straight. This evening I blew a head gasket, oil is foamy and milky. Is it going to be worth changing the head gasket rather than finding a used engine and transmisson and swapping. The truck has a 3.9 auto, and 213,000 miles, was running low oil pressure but no smoke. What all is involved in changing the head gasket other than the gasket sets and time involved. With an engine and transmission change wll I also need to change the computer or other electrics? Which would be better to do considering the mileage and all?
Thanks for any advice and help you can offer.

 

The head gaskets arent horrible. Time consuming, and youll need new head bolts because they are torque to yield bolts. Also a torque wrench and factory service manual.

If you upgraded to a v8 you would need a new computer, the engine side harness.

 

Fixing the head gasket is definately easier than swapping motors and a trans. My first time took me 2 full long days, after that I was able to do it in less than 6 hours in the dark by myself. You can buy a head gasket kit with all your gaskets. While you are in there you can also change the bypass tube for the water pump.

And if you upgrade to a V8 you will need a new trans.

Depending on how bad you overheated, if at all, the heads could be checked for flatness.

 

Seemed the head gasket would be easier, just concerned about the high miles. What should be done to clean the sludge out of the engine?

 

Is there really a lot of sludge in the engine? If it had regular oil changes with quality oil, there shouldn't be any oil sludge. The proper way to get rid of it if there is a lot is to change the oil in shorter intervals to let the fresh oil clean the sludge out. The improper way is to mix kerosene with the oil... which will cut the sludge out too quickly and it could clog up the passageways and bearings. The only other option is to do a full tear down of the engine and get it hot tanked.

 

Thanks, but the sludge I was referring to was caused by the gasket blowing and the coolant mixing with the oil. Is it necessary to do anything special to clean that out. The oil is frothy.

 

Oh, well I'd say change the oil, run the engine until it gets up to temp and change it again... and replace the filter both times... and you should be good to go.

 

You mentioned you were running low oil pressure too. I would probably at least check the oil pump to make sure you're getting proper lubrication to the engine. Could be as simple as a clogged pick-up screen. Of course that will entail dropping the oil pan and replacing that gasket as well but, that's not really a bad thing because that will help get more of the water out of the oil and give you a chance to check other engine components while the pan is off. You know check for metal shavings in the pan and check the bearings for wear. You said the engine has 213k miles on it. I think it would be well worth the extra couple of bucks to do especially before it gets too cold to work on.

 

It is going to smoke for a long time after you replace the head gasket so just be prepared. And like 95_318slt said, change the oil after soon. I'd say after it stops smoking.

Frothy oil is just the coolant mixed in. Btw, if you want to isolate Which head gasket went bad before you dossassemble pull the wires and spark plugs and crank it over. You should see a geyser of coolant come from the cylinders which have been affected.

I blew my head gasket earlier this year 10 hours from home. Towed the truck back. I worried too much about the repair. It was very straight forward.

Did you overheat bad?

 

I know it wasnt a magnum, but the 318 from a 88 diplomat/police cruiser blew the head gasket on the drivers side. Since that was a carbureted system it was easier to tear apart. However, I was sold the wrong head gaskets and ended up with an oil pan full of oil and water. I was a little less than happy. I let the water oil drain out completely while I ran to the parts store and got the correct head gaskets and quickly reassembled everything else. And as stated before, I poured fresh new oil in and let it run for about 30 or so minutes and surprisingly there was little evidence of water in the oil. I changed oil again and didnt notice anymore at the next oil change. Now, I personally reused the same head bolts again as I was dirt broke at the time and couldnt afford a new set. I just retorqued them to the specified setting and didnt have any trouble.