Leaking coolant from freeze plug

[aidachry2003]

Coach is a Monaco Diplomat 2003 -- diagnosis at Cummins was a water pump that was leaking coolant. After repair and after pressure testing a leak was still there. Initial diagnosis is the "cup plug" or "freeze out" plug is leaking. The plug is behind the water pump and under the gear housing. To get to it, they must remove the radiator and the gear housing and the waterpump. Estimated time to replace plug is 30 man hours at $125 Initial estimate $5000 . That's a high price for $20 part

I was wondering if I could a product like BlueDevil Pour-N-Go head Gasket Sealer could be used in diesel engine, I have used this product in my automobile with very good results.

I believe that the leak in the freeze cup is a small one, the engine never get above 200 degrees but when engine reaches operating temperature the coolant leak slows down to a trickle . I am able to drive between 200 to 250 miles before I get a low coolant alert only need to add about 1 1/2 gallon coolant.
Thanks in advance for your thoughts

[BigLar368]

If it were a freeze plug on the block leaking onto the ground then I would try the sealer however if it's leaking behind the cover would the coolant be leaking in the engine? If so then your loosing coolant and it's mixing with oil. Not a good combo.

[RobRoy]

Hmmmm?


Keep in mind I don't speak diesel, that being said here I go.

If this were spark ignition engine the first thing that comes to mind is why is it leaking?

Corrosion? If so what is the condition cooling system in general and also of all the other freeze plugs?

Did it freeze up? If so? what about the rest of the freeze plugs have they been compromised?

Im am not a fan of sealer's being added to cooling systems and if at all possible would not do so unless in a dire emergency.

Again I would want to know the cause of the leak before adding anything other than water or coolant.

Without hesitation, I would be getting a second opinion as to what is leaking and the cause.

Would I add stop leak? only as a last resort and had no other choice ... no other choice.

Others will chime in on a diesel cooling system sealer used by some here at iRV2 called "Iron(something)" that they have had positive results with using it as a band-aid to get them to where the leak can be addressed.

I feel your pain and understand the dollar thing being retired but again I would want to know why this plug leaked? ...is it a freak part failure? a bad part? cooling maintenance system neglect? poor installation? ..... You need to know the cause.

You add sealer and if it works for the time and then decides to fail when you 3k miles from home and ruins your vacation...and still costs $5k ....and likely much more towing, hotels and the likes....and your marriage ( jk)

Your need to inquire who is the best diesel tech in your area and pay them to diagnose your issue at hand.

You need a second opinion.......and to answer your question ...no I would not use Blue Devil.... and I have had engines torn apart that have used it and it is NASTY ...... but it may have stopped the leak.


Happy Hunting

[vito.a]

It's always tough to decide on a course of action on an issue like this. Freeze plugs are actually core plugs used in the casting process to clean out the casting sand.

The cooling system relies on pressure to keep the system from boiling. Even a small leak can release enough pressure to allow the coolant to boil at a lower temperature.

As long as it's not leaking into the oil, I would try all the inexpensive remedies first. Sometimes you can use a brass drift and tap an old freeze plug into the block just slightly and get it to seal. That's assuming you can get to it with a long brass drift?

Most folks will advise against any sort of coolant stop leak as it tends to plug the radiator tubes. I've used the old AlumaSeal successfully in race engines, but they have changed the product.

Can you find a small private shop in the area that works smarter or even at a lower labor rate?

[aguablanco]

"It's always tough to decide on a course of action on an issue like this. Freeze plugs are actually core plugs used in the casting process to clean out the casting sand."

Actually, I worked in a foundry for 10 years and there is no need to put holes in a casting to "get the sand out" there are plenty of ways to accomplish that. The freeze plugs are for freezing conditions so the coolant doesn't expand and crack the block. There are screw in plugs that I used many years ago that worked very well. I would not put any stop leak, etc in there as it all ends up in the radiator eventually. Get some bids and look around. Get it done right the first time.
RichH

[8.3Oilbuner]

Hi Frank: I assume you have an ISC engine. I just got home and after reading your post I went out and looked at the back of the ISC in my 01 Windsor. I see 1 small freeze plug above the water pump. It is about 1'' in dia. The next freeze plug I can see is in the head and about the same size. If the freeze plug is under the gear housing, coolant would be leaking into the oil. I also can't imagine a freeze plug behind the water pump itself! I can look at my engine since it has the side radiator. I agree with others that a second opinion is needed. The water pump sits in the block and is left of the gear housing. I would love to get a look at some pictures of an ISC with close to your engine serial number. To me some of the things you have been told do not add up. I know Cummins has a Tech line because I have called it before. Might want too Bing or Google the phone number and call and see if someone will talk to you. Have your engine serial number handy. See if they can send you pictures or a drawing of the block. I wish you the best of luck.

[RobRoy]

SOOOOoooo I do some snooping and find this old post ...it's almost verbatim

http://www.irv2.com/forums/f123/free...el-298781.html

Posted 07-08-2016, 05:43 PM





What am I missing

[aidachry2003]

Anyone know of a good diesel mechanic or repair shop in the Birmingham, Al area willing drive 100 mile to get problem corrected.

Secondly RobRoy I did use some of the wording from the post in 2016. Coach was taken to Cummins in Birmingham was told that the leak was coming from the water pump. had the pump and all the belts replaced at a cost of almost $1,500 was told that fixed the leak , but when we got the coach home we notice that coolant was still leaking. Took coach back to Cummins they did pressure was told that leak was from freeze cup was told that cost would be about 30 man hours at $125. Did a search found post from 2016 told wife this the same thing that we where told, didn't know whether to reply to 2016 post or created new one decided to copy wording from 2016 and create new post since situation was the same.

[RobRoy]

Originally Posted by aidachry2003

Anyone know of a good diesel mechanic or repair shop in the Birmingham, Al area willing drive 100 mile to get problem corrected.

Secondly RobRoy I did use some of the wording from the post in 2016. Coach was taken to Cummins in Birmingham was told that the leak was coming from the water pump. had the pump and all the belts replaced at a cost of almost $1,500 was told that fixed the leak , but when we got the coach home we notice that coolant was still leaking. Took coach back to Cummins they did pressure was told that leak was from freeze cup was told that cost would be about 30 man hours at $125. Did a search found post from 2016 told wife this the same thing that we where told, didn't know whether to reply to 2016 post or created new one decided to copy wording from 2016 and create new post since situation was the same.

Interesting ? and thanks for the clarification as I was a bit confused to say the very least.(and still am scratching my head as to why you would do so ...but ..whatever?)


Did you try and ask the original poster of that OLD 2016 post what the conclusion was to his IDENTICAL issue as you?


Did the repair facility of the misdiagnosis of your coolant leak at least offer any help ...with the freeze plug fix after their mi$diagnosi$?

Again ....you need a second opinion from another reputable repair facility

[Happycarz]

If you keep searching, you might find the post about an owner replacing that same freeze plug without removing the gear cover. It might have been a side radiator where access to it was out in the open, so all the labor time just to see it wasn't involved.

If you were to find a good independent tech familiar with Cummins at a lower rate and could show him this work around, maybe you would be able to save some money.

I would search for it if I weren't in the mountains with spotty and weak internet service.

[Happycarz]

Well, i found it. If link doesn't work search for "ISC coolant leak FYI" using the quotation marks. It is in the Cummins section from 10/15.

http://www.irv2.com/forums/f123/isc-...yi-266160.html

[guardrail53]

Originally Posted by Happycarz

Well, i found it. If link doesn't work search for "ISC coolant leak FYI" using the quotation marks. It is in the Cummins section from 10/15.

http://www.irv2.com/forums/f123/isc-...yi-266160.html

Thank you, Happycarz, for posting this! I will be doing some hard power washing in this area, to make sure it is kept clean! Who would of thunk it?
Most of the people with rear radiators don't understand the access issue, till they get hit with this type of labor bill! 5K just to replace a 3$ part! Wow!
It will still cost the side radiator owner to replace this little freeze plug, if they have a shop do it, but my guess it would a under 1K job! Way under!
Rail!

[RobRoy]

Originally Posted by Happycarz

Well, i found it. If link doesn't work search for "ISC coolant leak FYI" using the quotation marks. It is in the Cummins section from 10/15.

http://www.irv2.com/forums/f123/isc-...yi-266160.html

Thanks for sharing


I would be having a very very LONG hard chat with the upper management folks at the shop that misdiagnosed this one...............Wow! .....epic failure!

What appears to be more than obvious by the pictures and what appears to also be a pattern failure ta boot.

My guess is there may even be a Technical Service Bulletin on this one and if not?.... there should be, to at least inspect the freeze plug...or replace it.

I would think that with this happening that to replace that core plug
along with the water pump would be standard operating procedure, especially if a Cummins dealer or someone who claim expertise of the cummins product line.

[10Boomer]

Good to know, thx Harry.