Engine/Transmission (1998.5 - 2002) Coolant Slowly Disappearing

[PKleine]

About 3k or 4k miles ago I noticed the coolent level was low in the expansion bottle. When I opened the radiator, the coolent level was low, maybe 3 inches low. I refilled with both with a 50/50 mix of antifreeze/distilled water. Today the expansion bottle coolent level has dropped some, 2" and the coolent level in the radiator is down about an inch. Not sure where it's going since there is no smell or signs of leakage. Only place I haven't looked is the back side of the head. The engine oil level is about where it should be and it does not appear to be contaminated with coolent (I've seen antifreeze in the oil of a old 6. 2 gmc). Any of you folks have any ideas as to whats going on?



While the expansion tank doesn't look like it's been overfilled and vented some coolent overboard, the radiator cap seems a little strange. The rubber seals and relief spring are free to rotate in the cap, is this normal? Maybe I just need a new cap?



Thanks in advance.



PK

 

[AKAMAC]

Mine did the same thing. I assume that you have the OEM coolant in and your mileage is around 45k. I think my first post here was about this. Mine "drank" about 1 gallon before it settled out.



Try filling the radiator and over filling the over-flow (about 3/4 full) and check it when the weather is warm and the truck is cool. The system capacity is a little over 6 gallons, that is alot of fluid to fit in there. If it continues to use coolant then you have problems! Good luck, Mike

 

[HBarlow]

Mine used to do the same thing. Once I was afraid I had a cracked 53 block casting (it's not a 53) and then I was worried I had a leaking head gasket. The only problem I ever found was the radiator cap leaked very, very slightly when tested at 15psi. A mechanic friend explained that if the cap leaks very slightly I would never see evidence of the leak. I don't remember now if coolant loss ended after the new radiator cap or if it just went away. In any case, it is usually nothing to worry about. My truck now has almost 152k on it and doesn't lose coolant any more.



Harvey

 

[ak_fleming]

You can lose fluid if the radiator cap doesn't fit properly. The fluid will "steam off". I would try a new cap first since it's an easy and cheap fix.

 

[PKleine]

Thanks for all the responses. I will replace the cap today and take a 400 mile drive and see what happens.



PK

 

[swalls]

if you are still losing coolant, get an engine oil sample kit and pull a sample. The lab will tell you if there is antifreeze residue in the crankcase (which would suck, but wouldn't you rather know?)

 

[juicedcummins]

If it is a #53 it might be seeping!

 

[2-ND TIME]

I have the 53 block and it has been doing it since new. Just more bad thinks from the dredded two.

 

[PKleine]

Well, I finally received the new radiator cap ~$12 delivered :--) Local dealer didn't stock them. I will put it on and see what happens.



I also looked at the possibility of having a #53 block. Near as I can tell I do NOT have a #53 block There is no sign of the dreaded 5 3 numerals, just a bunch of other characters.



I sure hope the cap fixes the problem. Thanks for all the suggestions, this site is great.



PK

 

[Weidner]

I had a low coolent issue for a year. Every oil change at least, I would have to add a good amount. The truck would get low enough that my fan clutch would be engaged in city driving, even when it was cold. I could not find the leak at all. I could smell it every once in a while, until one day... . steam at a stop light and strong smell, went to the next light, hoping it was a car next to me or something, but it was me. After a close look, it was the tiny casting/freeze plug at the back right corner of the head leaking. My dealer, after the tech looked at it in the lot, had me leave it there on lunch. By the time I made it back to work in a loaner car (2 miles) they had already called and had it fixed. Don't let anyone tell you the head has to come of if that is the problem- that is B. S. It cost me less that $50, and the dealer gained my trust.

 

[TedStephens]

I have noticed twice after replacing the coolant in my radiator that the cooling level may be fine for several weeks, then drop once or twice very noticeably in the recovery bottle. I am guessing there is a vapor lock somewhere that finally clears. My temp gauge has behaved normally during this period. I have drained a quart of oil into a clean clear container and have seen nothing but good old oil. The exhaust does not seem to show moisture. Also, with the rough gauge of filling old containers with used coolant, it has appeared that my truck has given more in draining than it has taken, initially, while refilling. This adds to my thought that we get a bubble sometimes that will take a month or so, and several thousand miles, to clear.



Ted S, Yorkville, CA. 2001 3/4 Ton 4x4 Six Speed 100K Miles. This is my second TD. First was a 1996, 3/4 Ton, 5 Speed I put about 160K Miles on before getting the 2001.

 

[mpwalker]

Engine coolant loss

I have a 2005, 3500, cummins with auto trans dually and the coolant bottle is empty about every two days, never see any under the truck but today took it to a local dealer for replacement of the rubber molding around the doors and asked them to do a pressure check. They called two hours later and said it was leaking around the drain plug in the radiator and since it has plastic threads they were afraid to take it out due to maybe damage to the threads and that I must have a new radiator. It only has 15,000 miles on it so warranty will pick up the tab, however they say it will take 3-5 days to get new one in. They did not want me to drive it, but I took it back to campground because I have been driving it like this since it was new and could not get any dealer to listen to me. The temp gage always has worked ok and the temp never exceeded 210 even in the mountains pulling 12,000 5iver. Hope the dealer is not just looking for warranty work.

 

[PKleine]

Here is an update on the disappearing coolant problem my truck is having. With the the radiator full, the expansion tank up to the full line and a new radiator cap in place; the coolant is still disappearing. I made an appointment at the local dealer for their assistance with the problem. They kept the truck over night running a leak down test. They checked the oil and said it looked OK, researched the TSB's and service bulletins and came up empty handed. They could not find anything wrong with the cooling system and reluctantly informed me of their finding. I suggested that since the coolant was due to be replaced that they go ahead and drain, flush and refill the cooling system with new coolant so that they would be involved with the problem. They agreed to do that. When I went to pick the truck up, the service rep told me they did not change the coolant. His tech said it would be a waste of time, coolant and $$$. Instead they refilled the radiator and filled the overflow tank to about half way between the full line and full and said to monitor it. The service rep then when on to tell me there have been some rare occurences of some small cracks in the head that will only leak when the engine is hot. He then discretely showed me the time sheet for the labor he had in the truck and said that he wasn't going to charge me for the visit. He expects I'll be back for a warranty claim...



That was friday afternoon. Saturday, I changed the oil and noticed two very small drops of something floating in the oil at the top of the filter. I wish I had taken an oil sample before I dumped the crankcase oil.



I suspect the service rep is right about a warranty claim because this morning when I checked under hood, the coolant level in the overflow bottle was half way between the full line and empty. The level in the radiator was 2-3 inches below the top of the neck. I will be back in town tomorrow (Wednesday) so we will see what they have to say this time.



Has anyone ever heard of the cylinder head cracking problem?



Sorry to be so long with this post.



PK

 

[BarryG]

PK:

This may be a long shot but I had a problem as well. It was not nearly as drastic as yours. Mine would lower the level in the overflow bottle over a long period of time. I could never figure out where it was going. Oil checked out. Never could find evidence of a leak. I ended up not worrying about it. After about 2 years the truck was in the shop for a valve adjust. I was out of town while it was in. When I went to pick it up they said they went ahead and fixed my coolant leak. I said you found one where? I had looked for quite some time and could not find any evidence of one and had given up but that I had been loosing coolant slowly. They said it was the thermostat. That it was leaking from the housing. They noticed a trail that I had never noticed. They put in a new thermostat (it has the seal ring as part of the thermostat) and since then no more coolant loss.



It might be well worth your while to go ahead and take an oil sample and send it in to find out if there is coolant in your oil. Your warranty is ticking a way. You may run out of time well before you run out of miles since yours is an 01 and we all know a dealer would not push a warranty item off until the the warranty runs out, would they? Some would stand up and deal with it but others would not.