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Topic: Radiator Cap Slobber (Read 861 times) previous topic - next topic

Radiator Cap Slobber

 >:D >:D  I'm having a new problem with the radiator slobbering from the pressure cap, the expansion tank seems to be working as it should and not over full. Could it be a weak cap spring? or has anyone had this problem with a Detroit 6V 92? ???
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Gerry & Brenda
CHARLOTTE HARBOR, FL
1994 Grand Villa - # 4466
U300 Unihome - 6V92 Detroit
4 speed Allison - Jake Brake

Re: Radiator Cap Slobber

Reply #1 –
Sounds like the gasket is worn out, loose or broken.  A new cap with a good gasket would be my thought. The gasket is to make the recovery tank work, gets hot, push water into the overflo tank when cools down it pulls t water back into the radiator.

We need a word smith who understands the system, to rewrite this.
Carol or Neal ?

Re: Radiator Cap Slobber

Reply #2 –
Quote from: Dave M –

We need a word smith who understands the system, to rewrite this.


Radiator Caps
The selected media item is not currently available.Barry BEAM #16014
2003 U320 40' AGDS
Beamalarm, Foretravel technical help and specifications
"Whatever the mind can conceive and believe, it can achieve"

Re: Radiator Cap Slobber

Reply #3 –
I've had this problem and it looks to be solved.  As Dave says it's the cap but you need to inspect the filler neck sealing surface for any nicks and bends that would cause the seal not to work.  Also check the overflow tube for cracks.
I have a 10 PSI cap but don't know if that was the OEM pressure.  Anyone know what it's supposed to be?
John Fitzgerald
1991 U300 (SAI) Side Aisle Island Bed 40'
Detroit 6V92 with Allison Retarder
Meridian (Boise), Idaho

Re: Radiator Cap Slobber

Reply #4 –
Thanks I'll be getting a new cap tomorrow.
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Gerry & Brenda
CHARLOTTE HARBOR, FL
1994 Grand Villa - # 4466
U300 Unihome - 6V92 Detroit
4 speed Allison - Jake Brake

Re: Radiator Cap Slobber

Reply #5 –
My cap is slobbering too. I plan to replace it soon but can't find the PSI on the cap so like John if anyone knows the proper PSI on a 6V92 radiator cap please speak up.

see ya
ken
The selected media item is not currently available.ken & dori hathaway & Big Agnes
🍺1992 U300 GrandVilla WTBI #4150 FOT FBP 2011
✨6V-92TA DDEC Parlor Coach 350HP Series 92
🏁2011 Nissan XTerra Pro-4X

Re: Radiator Cap Slobber

Reply #6 –
If you have ever seen one of those testers that a auto mechanic uses to slightly pressurize a cooling system with a plunger-style pump that attaches to the radiator/expansion tank, to then track down coolant leaks -- these also are great for testing a cap to make sure it doesn't release until the pressure reaches the cap rating that appears on the top of the cap. The tester had a dial type guage on it.

It used to be -- the better Auto Parts stores kept one under the front counter just for that purpose.
Michael
1995 U300SE CAT 3176B Build # 4612 ("Marvin")

Re: Radiator Cap Slobber

Reply #7 –
Quote from: kenhat –
My cap is slobbering too. I plan to replace it soon but can't find the PSI on the cap so like John if anyone knows the proper PSI on a 6V92 radiator cap please speak up.

see ya
ken
Thought this was going to be easy to answer.  But came up empty.

If you really need, I can make a couple calls and know I can get the answer to which cap goes on the 1990s era DD 6v92 in a White Road Boss II road tractor.  I know the psi is critical and if it is to high of psi, you will find hoses leaking, and to low of psi and the cap will be leaking all the time.  I don't know if these are critical to the vehicle they are in, or not, but would not be surprised.  You would have to ask Detroit Diesel that question.  There were lots of the 6v92s in bus duty, so I would think a cap that fit one of those would work.

Edit:  Okay, got told it depends on application - There are two different sizes.  The old style is large and the new style is small.  Don't know the year change over for that.  Best to call Foretravel.  Am sure the psi Dave said below would be safe.
1994 U225
build #4514

Re: Radiator Cap Slobber

Reply #8 –
10 psi Recovery cap should do fine

Re: Radiator Cap Slobber

Reply #9 –
I fought an expansion tank leak at the cap since purchasing our coach. It was only evident when pulling hard through the mountains. After beating my head against the wall I finally discovered the even though the cap was new and the neck was in good shape, it still could be slightly rocked side to side, when seated in place. I removed the cap and bent the lugs upward. Cap when on much tighter. Has not leaked a drop since.
The selected media item is not currently available.Bob & Faith Rozek
1997 U320 40'
Xtreme Remodel
2010 Scion XD

Re: Radiator Cap Slobber

Reply #10 –
My coach is a 10 PSI as Dave said.
2025 Wanderbox Outpost 32 on F600 Expedition Motorhome
2015 Born Free Royal Splendor on Ford 550 nonslide version  for sale
Former Coaches  covering. 360,000 miles
1999 34 U270
2000 36 U320
2001 42' double slide U320
2018 Jeep Rubicon

Re: Radiator Cap Slobber

Reply #11 –
@Bob thanks that seems like a real possibility. I'll check it the next time I'm at the coach.

@John thanks for confirming the 10 psi.

see ya
ken
The selected media item is not currently available.ken & dori hathaway & Big Agnes
🍺1992 U300 GrandVilla WTBI #4150 FOT FBP 2011
✨6V-92TA DDEC Parlor Coach 350HP Series 92
🏁2011 Nissan XTerra Pro-4X

Re: Radiator Cap Slobber

Reply #12 –
Gerry,

I have the same problem with my 6v92 radiator cap spitting a few drops from time to time.  I cleaned and lightly sanded the neck filler surface and replaced it with a new 7psi cap. It got worse so I bent the tabs in a little on the old one and tried that and it almost stopped it.  I will replace it with a new 10psi as others have recommended and see if that does the trick.  I believe a 10 psi is the correct one.  Will let you know. 

Jerry
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Jerry and Cindy Maddux
1993 U300/36WTBI DD6v92TA
build 4271  "Miss Lou"
1995 suzuki sidekick 4x4 toad
Gulfport, Ms

"Pride of Ownership"

Re: Radiator Cap Slobber

Reply #13 –
My radiator cap doesn't slobber.  The last owner replaced it just before we picked it up.  But I don't see any coolant in the overflow/expansion tank even when at temp.  The coolant level is right up to the cap on the tank (when cool.). Do I need more coolant?  Maybe a new cap?  How do I know if it is a 10psi cap?

Thanks
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN
 

Re: Radiator Cap Slobber

Reply #14 –
Quote from: Home2fromHastings –
My radiator cap doesn't slobber.  The last owner replaced it just before we picked it up.  But I don't see any coolant in the overflow/expansion tank even when at temp.  The coolant level is right up to the cap on the tank (when cool.). Do I need more coolant?  Maybe a new cap?  How do I know if it is a 10psi cap?

I recall this thread by Barry B.  regarding 2-gasket rad caps.  Possibly something to investigate.  I would think there should be coolant in the overflow - at minimum it should be at the COLD line when cold.

Cummins M-11 450 Engine Overheating
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320