Help- Overheating

[rowland]

Started my truck this morning and everythings seemed to be fine. Shut it down for an hour and when I fired it back up again the heater didn't seem to be working properly. Drove for a little ways before noticing that the engine temp gauge was going through the roof. I wasn't far from home so I pulled over and let it cool off before limping the rest of the way.



Checking under the hood, the radiator was ice cold and I was getting coolant spraying out the cap on the overflow container.



I am assuming that the Thermostat is failed shut. This seems a little odd, (aren't they supposed to fail open?) but that is all I can think of. Truck has 83,000 mi on original thermostat, and the temp this morning was 0*F.



Anybody out there had this happen before? I can't get parts today (easter) but will be attempting to fix in the near future.



Thanks



Rowland

 

[paccool]

Have not had that happen the the truck but it did happen once to me in a car. Sure sounds like that is the problem. I seem to remember a post about this and that there was a change in the thermostat design to correct this. If the search engine was working you could do a search for this. Maybe someone will help us out here.

 

[Fossil]

I had a T-stat snap shut on my gasser Dodge P-Wagon once.



They will fail in the open position normaly. but as I found out, if the 'yoke' where the wax pellet housing breaks on one end, they will fail in the CLOSED position... ... Major Bummer.



On mainline I-5 in rushour traffic when temp went to the moon.



3 miles to nearest exit then one more to station.



Just held it to the floor while coasting, pulling in cold air/fuel to keep from frying the engine.

 

[83 crew cab]

rowland about the same thing happend to me acouple weeks ago but it was also haveing swings in the temp when the eng got hot enough the termastat would open way to late



go to cummins and spend the $25 for a new on comes with the oring I tried 2 from parts stores one bing napa till I gave up kept have temp swings but no over heating fixxed everything thang with the cummins thermastat George

 

[rowland]

themostat

Thanks for the info, I also noticed temp swings above normal for about the last month and have been meaning to replace the thing. However, working on a truck is difficult in a college dorm parking lot, esp. in the winter. Guess I have no choice now. I am going to try to find a cummins part in town as I have also had bad experiences with Napa stats.



Thanks for the help guys, I knew that it was supposed to fail open so I thought that I should check before I started taking things apart. Any special tricks I should know?



Rowland

 

[CRWilliams]

Just a little tip I picked up a couple of years ago. If the t-stat fails closed and you can get to it by pulling the upper hose off, you can pop a hole in it with a screwdriver or knife and at least get home

 

[Tim1]

In my experience, most of the time these suckers fail in the closed position and cause alot of problems. There is a new t-stat on the market called the Fail Safe t-stat that will fail in the open position, however I wouldn't use it in our trucks. I have them in our cars and have put them in some equipment, but not the cummins. Just my thoughts. Tim

 

[rowland]

its not working!

I just replace the thermostat this afternoon, it went well except that is still overheats! Checked the coolant level in the radiator, it seemed a little low, so I poured anouther gallon in without any trouble.



I ran it again and it started boiling out my reserve tank. This is not good.



So what did I do wrong? Did I aireate the coolant in the block? Whats the deal?



Oh, also the thing that was causing the other stat to stick was a piece of sand. Not sure where that came from.



Rowland

 

[BushWakr - RIP]

I think you may want to drain, flush and re-fill. You obviously got some junk in the old T-stat, maybe theres more in there.

Was it sand or something else?? Catch what comes out of the drain plug and check for stuff in bottom of catch pail.

On another off chance, aside from water pump problems, check this out.

On my truck when it was flushed some years back by the dealer, the mechanic said that sometimes they get an bit of 'airlock' as he called it.

If I remember right, on the front of the head, or on block just in front of head is a plug that has a 1/4" or 3/8" allen center. (Its dark and raining right now and I can't go look). He slowly loosened this out just as the T-stat started to open. He didn't take it out, just loosened it enough that a bunch of bubbles/water kinda spurted out. When there was no more bubbles, he tightened it back up.

Like I said, I've no idea if this was a legitemate deal, myth, or what but, it did spout bubbles,air, then water finally.

Just trying to help.

Let us know how you make out.



Bob

 

[CrewCabDiesel]

Try back flushing and bleeding the system as BushWakr suggested. Also check the water pump to see if the impellar is still turning(yea I know you have to take it off). If everything checks out, head gasket ?

Kyle

 

[rowland]

$$$$

Well the news seems to be bad. Today I filled and bled everything, rechecked the thermostat and tore off the water pump. Everything checks out good, but when I fire it up, it blows air and water out the radiator and into the reserve tank. ALOT of air and water.



I will run a check tomorrow, but it looks like overheating it might have blown the head gasket. I am not real happy with this development but I guess that I am going to have to deal with it. Does anybody know what this would run? I can't really do this myself in the parking lot, so I reckon I will try to find a truck shop to do the work.



I'm a little poor right now, so if anybody has any other ideas or a way to reduce the pain in the wallet, that would be great.



Thanks



Rowland

 

[CrewCabDiesel]

Sorry to hear that,

When you go to get parts, SKIP NAPA, get the gaskets and other parts directly from Cummins(especiality the thermostat !) Take the head to a good machine shop and have it magna fluxed and check for warpage , DO NOT skip this step, it is better to spend a couple bucks for the magnaflux than pull the head for a second time because of a hairline crack. I know this is not the cheap way, but you will have your confidence back in your Cummins

 

[Thierry]

what year truck? as the older heads with the large injector nozzles were prone to crack, they can be repaired but expensive to do, usually means replacing the head to a newer style 91. 5-93



good luck and keep us posted.





Thierry

 

[rowland]

hot air

Played with it somemore yesterday, even went so far as to take the bleed plug all the way out and watch it run. Something is pumping alot of air through that block, but no water. Since I can't think of anything that is SUPPOSED to pump air out of an engine head, this can't be good. I'm pretty positive that it is the head gasket now, dang it. Am waiting for a call back with a estimate from the local diesel shop. The good news is that I can't see any coolant in the oil, and the exhaust doesn't smell funny.



Thierry:



Truck is an '89. I will have the head checked when they take it off. If I have to get a new one, will my old injectors, etc. still fit?



Thanks for the help guys



Rowland

 

[Thierry]

if your truck is an 89 you are using the larger nozzle injectors and if you cant get your head fixed you will have to get a new set of injectors.

I was able to get a complete set of injectors from city diesel for $245 shiped to the door. keep this in mind if you have to go new head.



Wait and see what happens?



Thierry

 

[CrewCabDiesel]

Sorry , the new heads are a 7mm, 1989 to 1991(early) are 9MM. So if you buy a new head, better figure on some new injectors . And stock 7mm injectors are gutless, so best ones to get (if you have a intercooler & gauges) is the Lucas PODs.

 

[Gary - K7GLD]

You had better STOP operating that engine until you determine what the problem actually IS! IF you DO get some accumulated water in a cylinder, then start the engine, you stand a EXCELLENT chance of hydro-locking it and ruining a piston/ rod/crank - possibly the WHOLE engine!:--)

 

[rowland]

Update

Well, for all you guys that helped me out on this one, here is the latest. I pulled in some favors and got the truck on a flat deck headed down to Palmer (320 mi. ), where I know a good cummins mechanic. He pulled the head and today informed me that it has a great future as a boat anchor but not much else. joy.



He is attempting to find a good used one locally, and if that doesn't pan out he will be ordering one from the states. Am probobly going to end up putting the old style (9mm) head back on just to save having to buy injectors. Will be installing a mechanical temp gauge on the dash were I can see it ASAP.



Well thank for the help everyone.



Isaac.