coolant system pressure testing

[Hank]

Does anyone know how to pressure test the cooling system on a MCI 96A3? The manual doesn't talk about it. It does state that the relief valve setting is 7psi. The filler cap is not a conventional type pressure relief cap and best I can tell, it doesn't look like the filler neck would accept a pressure cap type pressure testing adapter.
I would appreciate any wisdom on this.
Thanks!
Hank

[Slow Rider]

Bump

[buswarrior]

Hello Hank.

Why are you wanting to pressure test?

Do you have a tire valve style schraeder valve on one of the coolant crossover pipes on the engine?

An 8V71 has one right at the back, between the vee's (back of the bus, not the engine) where you could attach a tire pump to put a few pounds in. Be VERY careful if you are messing with your shop air, too much is not good!

happy coaching!
buswarrior

[Sammy]

Check along the bottom of the radiator surge tank.
I have seen a schrader valve (like a tire valve) mounted on the bottom of a surge tank in a MC12.
REMEMBER - only 10psi or LESS is needed, Do Not hook directly to shop air line.
I pressurize cooling systems with a tool I fabricated. It has a check valve, an air pressure regulator, an air pressure guage (0 to 15 psi), and a short line on it. I modified a few surge tank fill caps to accept a brass fitting - this is where the tool hooks up the cap to introduce air pressure to system.
I put them on 6V92's (quick release style fitting) in water jacket of the cylinder head. I put them (quick release fitting) on Series 50's mounted on the water pump or cylinder head water jacket, and Series 60's in the cylinder head water jacket also. You can basically tap into the cooling system in the most convenient spot for your application.
Use brass fittings, pieces of line, make support brackets to mount the quick release fitting in a good,safe location, or right on the engine.The male half of the quick release fitting will remain on the bus. the female half of the fitting will remain on or with your testing tool. The fitting is like a high pressure hose disconnect type - like a snowplow set up - nothing fancy, works great.Make sure the fitting is rated for at least 300 degrees F. Try an industrial supply house, truck parts house, etc. I'm sure if you tell them what you're fabricating they will be able to steer you in right direction.
Hope this may help. 

[Hank]

Thanks guys! Yes, I do have a schrader valve that is mounted along side the engine room access door, near the remote starting box. I have pushed on the valve stem in the past and wondered why coolant came out...now I know.

Why pressure test? It's actually for a school project. I'm in a two year full time diesel technician program at our local tech school and this is part of a PMI course. I've run full coolant system diagnostic tests on several semi tractors checking freeze protection, SCA levels and pressure testing, etc.,  We use a shop air to radiator cap adapter kit that has a pressure regulator and check valve. The cooling pressure relief valve is set for 7psi on my bus but the manual doesn't mention anything about the schrader valve or pressure testing.

They let us bring in projects if it pertains to what we're working on. I've haven't changed the coolant since I got this bus and am taking this opportunity to do that.

And by the way, there should be no doubt in anyone's mind as to the importance of using antifreeze designed for heavy duty diesel engines with wet sleeves. We got to examine a bunch of cylinder liners that failed due to cavitation erosion because automotive type coolant was used in the coolant system. Very expensive failures that could have been easily avoided by using the proper coolant (this is part of what prompted me to do this!).

I appreciate the help. Someday when I'm a little more seasoned, I hope I can return the favor.
Hank

[Lin]

I thought that there were additives that could be put in with the regular coolant to prevent cavitation.   I have some a Napa product called "Cooling System Treatment 4058" that I was told to use for that purpose.

[Kristinsgrandpa]

  This is an opportune subject for me as my radiator is being recored, and I intend to replace my antifreeze.

I believe there are test strips that can be used to check the antifreeze. The local NAPA operator told me that they have the additives and I would like info on what test strips to use.
My calculator will probably determine whether I use the DD antifreeze or just add the necessary ingredients to Prestone.

Also the compatability of the two is a major issue if on the road and need to replace lost fluid.  I intend to carry extra, but.....

My NAPA operator has worked this store for about 20 to 25 yrs. and I trust her on most things, but she is not a diesel mechanic.

Ed

[Busted Knuckle]

  This is an opportune subject for me as my radiator is being recored, and I intend to replace my antifreeze.

I believe there are test strips that can be used to check the antifreeze. The local NAPA operator told me that they have the additives and I would like info on what test strips to use.
My calculator will probably determine whether I use the DD antifreeze or just add the necessary ingredients to Prestone.

Also the compatability of the two is a major issue if on the road and need to replace lost fluid.  I intend to carry extra, but.....

My NAPA operator has worked this store for about 20 to 25 yrs. and I trust her on most things, but she is not a diesel mechanic.

Ed

Well yer right she may not be a diesel mechanic, but she may know 1 or 2 & has probably even sold a part or 2 to them! LOL! Just ask her for the antifreeze coolant test strips that they use, as far as I know there is only one type of test strips. But I'm no Napa parts dealer! LOL!

[Kristinsgrandpa]

Thanks BK.  I usually trust her but wanted some part numbers if available.  Lin gratefully provided one for me. Thanks Lin.

Ed