Overheating

[Johnm]

I have a new issue with my truck and am at a loss as to what is going on. I am over heating and seam to be loosing coolant but it is not in the obvious places. I replaced my thermostat and thought I had it nailed. nope still over heating. Then I thought I had a vapor lock and bled the head again by removing the plug on the head right behind the thermostat housing. still not the trick. I thought maybe it was the fan clutch, but it gets way to hot to just be that and I can see that the fan is still moving air. the truck is an 89 d350 5 speed man

 

[Exekiel69]

how fast do You loose the coolant? I assume it must not be much so You can't tell where it goes. What about the radiator? When You replaced the t-stat You made sure You installed it right? there is a small passage You need to leave open and the t-stat must face the right way. That much I know, hope it helps.

 

[Johnm]

I pulled the stat and i am still overheating and loosing fluid. i think i might have a cracked head. between the exhaust valve and the water jacket. i think i am loosing fluid when the engine gets hot and it is evaporating and going out the tail pipe. it seams to be the only logical explanation. now i need to figure out the best way to get a new head and decide if i want to take on the project of swapping the heat on myself. how bad is a head swap on a cummins?
the only thing that freaks me out is the valve adjustment i imagine i would have to do if i swapped heads

 

[rebel_horseman]

If you get an aftermarket head from a vendor the valve adjustment may not be necessary at all. With my stock head at 165k miles it didn't need adjusting.

I've never pulled a head out of one of these trucks but it honestly doens't look difficult since it's pretty wide-open and easy to get to under the hood. If nothing else, take it to a local Cummins shop and have them look it over.

 

[argve]

Having not pulled the head on mine I can't say how easy or hard it is (2nd gen) but looking at mine it really doesn't look all that difficult and seeing it apart in the shop when they were doing the work it really didn't look all that daunting of a project (I was just tired of doing engine work at the time). My bet would be that you have a warped head which seems to come from the exhaust manifolds heating and cooling cycles - what we seen on mine was that the exhaust manifold had peeled the head up on the front (#1 cylinder) so that water could escape and the bolts that hold the exhaust man in place were bent. I have seen the same thing on my buddies '99 (24v) we caught his before it lifted the head - the front bolt on his was a real pain the patucks to get out - it was amazing it didn't snap the bolts off.

but before I would go and start yanking things off I would at least pick up some dye from the auto parts store and put in the rad and let it run around for a little bit then crawl under the hood in low light with a black light and look for glowing spots from the dye to help troubleshoot. That's a lot cheaper and easier to start with than just yanking things apart.

 

[Johnm]

thx guys, if it is a cracked head, does anyone have a good place to get a replacement? i saw one with porting work done, but i am unsure how much bang i will get for the extra 750 dollars

 

[Jared]

Have you pressure tested the cooling system yet? if you have a pressure tester, hook it up dont pressurize but start the truck. If the pressure jumps up quickly you have a head problem.

 

[Johnm]

got some really bad news....My cummins is officially a paperweight. i got the truck used and i pulled the head for this issue. the head was junk and so was the block. this thing got really hot at some point. prior to my issue says my machine shop guy.
so that is the part that sucks. now for my new plan to put her back on the road. i am going to drop a 96 engine in my 89 1st gen. when called the wrecker and asked for a first gen he said, why dont you just swap a 96 engine into it. the only part i will be missing will be the intercooler and the wrecker just happened to have a 90 d350 with a banks intercooler in it that he parted with for 200 bones

 

[h2odrx]

sound like things are looking better?

 

[Johnm]

it will be with the new bullet in the box...cant wait to play with the 96 engine