Engine/Transmission (1994 - 1998) Bubbles in overflow losing coolant

[JHastings]

Pretty sure I know what this is, but just want to make sure.

I have bubbles in my overflow tank. No oil in coolant, but it has been using some coolant too.

It got hot twice this summer. Up around 210*. It had never done that before.

I have a copper headgasket so I have heard that they don't seal liquids as well.

1. So is it blown?

2. If it is and I need to get the head machined flat, will I have to cut new o-ring grooves?

3. Do I go with the marine 0. 10 gasket this time?

4. Can I reuse my studs?


I am going to drop the oil today to see if there is any water in there.

TIA
Jamie

 

[ewcmr2]

I'd get the oil analysed (blackstone or similar). If water gets in the oil and you run it hard the water will evaporate out of the oil leaving the abravsive additives from the antifreeze but no visible sign.

 

[Missouri Mule]

You can (or have someone) do a compression test. You have to pull the injectors and have a special adabter.

 

[JHastings]

Where do I get the special adapter or do most compression kits have the correct adapter?

Jamie

P. S. I am thinking that maybe it is a cracked head. BTW I have been driving it for some time now just as daily driving and it never gets hot. Only when I am hauling.

 

[JHastings]

This pickup is doing some weird stuff. I filled up the coolant bottle and now the truck runs cold. About 170*. Sometimes it will get up to about 190* and then immediately come back down to 170*.

Could I just have a faulty thermostat?

I think I have seen posts about temps jumping all over the place before.

 

[Missouri Mule]

With the original thermostat because of the size of the radiator tempature swings from 150 to 180 are normal.

Cummins has upgraded the thermostat so the tempature swings are less.



You would have to buy the adapter separate.

 

[JHastings]

I borrowed a coolant system pressure tester. Any advise on this?

Will it show a cracked head?

 

[Missouri Mule]

Only if the coolant can make it past the head gasket to where you can see it.

Also it could be a heat crack which would be hard to find.

 

[Signal73]

most likely headgasket. get rid of the copper one they are not friendly at all for daily drivers.

 

[JHastings]

Gosh that would be great if that is what it is. Will this coolant system pressure tester find that?

If it does leak down, do I have to look in the cylinders to see if it is going in here or just start by taking the head off?

Jamie

 

[Signal73]

Gosh that would be great if that is what it is. Will this coolant system pressure tester find that?



If it does leak down, do I have to look in the cylinders to see if it is going in here or just start by taking the head off?



Jamie

its pushing out from the cylinder pressure. I dont know if there is enough PSI to make it leak down into the cyl itself with a tester but its worth a shot.

 

[JoeBioDiesel]

The problem with using a coolant pressure tester is that they have to move an awful lot of coolant to make the gauge move, so the're a crummy diagnostic tool for head gasket leaks. The exception on this is if you pull the injectors and have a borescope to check for coolant in the cylinders. You can leave the coolant system pressurized overnight then check for coolant in the cylinders. Most of us don't have a borescope kicking around though.

Lastly, if the coolant is leaking into the cylinder when using the pressure tester, you run the risk of hydro locking the engine.

So, if you truly have bubbles in the overflow tank, try using a CO tester on the radiator to confirm that it is combustion gasses. If it is, pull the head and check for a blown head gasket. Get the head checked while you have it off. Do your best to use a machine shop with Diesel experience.

Joe

 

[edgeman]

I noticed earlier in your post that you asked if you had a faulty thermostat. In my 97' I was showing signs of bubbling in my overflow bottle and also shooting coolant back out of the over flow bottle. I found that it was the thermostat pressurizing the system. I also ran cold on the engine temp side. And also the new thermostats swing more than the old ones. Just to squash that theory. My trucks thermostat swings from 140* to 190* and never stays in one spot. I would change the thermostat first and if that doesn't do anything then troubleshoot farther... . let us know what is going on!

 

[JHastings]

Cool. replacing the thermostat is a lot easier than taking off the head.

I'll let you know. Which thermostat?

Cummins #?

TIA

 

[JHastings]

Well, pressure checked the coolant system today and it seemed fine.

What did not seem fine was that my radiator cap (a 15psi cap) only held 7 psi!!!

Any chance that I was losing coolant when the coolant was probably boiling... hence the bubbles in the tank?

Going to start with a good cap tomorrow and see what happens.