chaikwa

Okay, this is a 'BDQ', (Big Dumb Question), but before I go tearin' my truck apart, where exactly IS the thermostat? Is it in the housing that the upper radiator hose attaches to, that also mounts the alternator? Or is it in the housing AT the point where the radiator hose attaches?

I suspect the first location I mentioned, but it seems like alot of work, (pulling off the alternator), to go thru, just to change a thermostat. And if it IS under/in this housing, are there gaskets that I will need to replace where the housing mounts to the block? I told the parts guy at Cummins to give me all I'd need, but all I got was the thermostat and a big rubber sleeve/bushing/'O' ring thing.

As long as I'm asking questions, any of you guys know anyone in the southwest Michigan area that 'knows' these motors and might consider working on mine for me. I know you get what you pay for, but I just can't bring myself to pay the almost $100 an hour to the dealership just for simple stuff that I'd like to learn/do for myself, like injector changes, timing, etc. This poor thing has 8700 hours on it and it needs some maintenance, but I'm just a tad scared to dive into it myself. If I screw something up, I have nothing else to drive, and this is a truck I make my living with.

The truck's a 93, 4WD 1 Ton, if that matters. <sigh>... nothing's simple anymore!

Thanks in advance!

chaikwa.

AlK

To replace the thermostat you have to remove the housing. According to my 92 service manual there are no gaskets other than the thermostat seal that should come with the thermostat. Make sure that you purchase the proper thermostat, because a number of individuals have purchased them from auto parts stores and they did not work properly. If you wish I can take a picture with my digital camera and send you some pictures from my manual.

As far as changing injectors, turbo housings and gauges go, I would recommend that you use the search function on this site and do a lot of reading. I am pretty sure that you may also be able to find other CTD owners in the area that you live that will be able to help you.
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Al

chaikwa

Thank you Al. I appreciate the response.

Pics would be most helpful and would be appreciated as well. No big hurry on them. It may be a day or two before I get to doing this. The truck isn't 'down', it's just not producing any heat and the guage reads on the cold side all the time until I really work it. I suspect the thermostat is stuck in a partially open position.

I got the new thermostat from the local Cummins dealer, so I HOPE it's the right one!

Thanks again!

chaikwa.

AlK

O.K.,
I will send you some pictures.

apache

Its easy,get a 3/8 drive rachet and unload your belt tensioner and slip the belt off the alt, remove the upper 10mm bolt fot the alt, and loosen the lower 14mm. it will swing down to the left enough to get at the thermo. there is a ground strap under the housing that has a 14mm also. Remove it for easy access. there are 3 ,10mm head bolts for the housing, 1 on top 2 on bottom, I think. it will be easier if you remove the upper hose from the neck before all this also. a light tap on the housing and it will fall off.
The rubber boot is the gasket. IT MUST GO IN ONE WAY.there is a small lip of sorts on one end. the directions will say or look at yours. There is no gasket for the housing. also read the directions for the correct thermostst installation direction. This will effect the operations if wrong. Also in the bottom of the box is a template to check the block for the correct hole size. on early mods some need the hole enlarged a little. very easy, if you can change your fuel filter, you can do this, have confidence

CB_Parker

I just did the job myself, because both my thermostat and return housings were leaking. The thermostat is a piece of cake, the return housing, on the other hand, is a PITA! You gotta slide the AC compressor out to the fram and stick a socket up there.... it just sucks.

Plus I did all that, now hoses, fresh coolant, new seals on both housings... just to find that the return housing is still leaking like a siv. I think some silicone on the casting is in order!

chaikwa

apache, CB_Parker, thank you. Between your advice and the pics that AlK is sending, I ought to be able to handle it! I'm gonna attempt this tomorrow, so I'll let you know how I make out.

Somehow, things like this seem a lot easier when it's not MY truck I'm doing the work to!

chaikwa.

apache

I know what you mean, I havent quite figured that one out. Dont feel alone

Alec

My problem is, when it is MY truck anything else I notice that might be wrong, or paint that needs to be touched up (read the WHOLE truck) or that speck of lint that maybe fell into the housing . . . it all becomes a big deal.

Somehow 'cause it's mine I expect to pass it on to my heirs and assigns . . .

chaikwa

Thanks everybody for your help!

I successfully (I think!) changed the thermostat this AM. It came apart just like you all said it would and the only trouble I had was the thermostat itself was stuck inside the housing. I had to use a pair of water pump pliers to twist and pry it free. I cleaned all the mating surfaces with a scotch pad, put it all back together and ran it at 1500 RPM for about a half an hour. The temp guage went up to the 2nd mark in the 'normal' range and stayed there. Then I took it for a ride. The needle went just barely past that 2nd mark, but not any higher. This is a big improvement over what had been happening; I could barely get it into the normal range at ALL!

When I got it back to the shop, I checked for leaks and so far, it's still dry. I haven't 'worked' it yet, (like pulling a trailer), so I still have to see what happens in that case, but I think it should be fine. It used to get 'uncomfortably warm' when I really worked it, I assume because the thermostat was only partially open.

I DID find a bunch of junk in the neck of the housing, but I don't think there's alot I can do about that. I don't understand WHY there's so much, because I've religiously changed the anti-freeze every year with Cummins pre-mix, flushing the system each time. I'm posting a pic and hopefully it will show up! (I've never posted a pic before!)

Thanks again guys, the help is really appreciated!

chaikwa.

chaikwa

COOL! The pic worked! hehe.

Redleg

chaikwa, do you get north very often? Pump tweaking isn't that bad to do. Start thinking about gauges, I can show you where they go too. You should get'em before you start giving it more fuel. I work in Rockford, live up by Big Rapids.

Don

chaikwa

Redleg,

I don't get up north very much, but I could.

I just moved out here from Mass about a year ago, and for the life of me I can't figure out where I am half the time! I'm just not used to everything being set up in 'squares' I guess.

But on a positive note, I've HEARD of Rockford and Big Rapids! I've even been to Grand Rapids a few times, but I have yet to find the 'rapids'!

Oh yeah, and everybody out here says I talk funny!

chaikwa.

Redleg

You's are gonna have to make a trip up if you're an outdoorsman. It's alot more scenic and wooded up north. If K-zoo doesn't have one, there is a Cummins shop in Wyoming when the time comes. A good turbo shop that supply's gauges too.