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Topic: Coolant Question (Read 637 times) previous topic - next topic

Coolant Question

I bought this coach at MOT recently. Before taking it home to Dallas I had them do a "Full Fluid Service". I assumed per there checklist this included a coolant flush and replacement. All that was done was check the "coolant protection level". So my question is this. When I finally had a chance to check today with the engine cold. As I slowly removed radiator cap some coolant started to come out so I tightened the cap back down. But there is no coolant in the recovery tank. Nor can I see a cold fill hot fill markings anywhere on the tank. Is this normal?
Thanks,
Robert
2008 Nimbus 342
Build# 6464
ISM 500
Allison 4000 w/retarder
2021 Jeep Grand Cherokee

Re: Coolant Question

Reply #1 –
You should add some coolant to the over flow tank and you may need to mark a
low level mark of your own.
Peter and Frieda Morin
1999 36ft. U320 Foretravel
Build # 5436
1998 Suzuki Sidekick Sport

Re: Coolant Question

Reply #2 –
Quote from: Res777 –
there is no coolant in the recovery tank. Nor can I see a cold fill hot fill markings anywhere on the tank. Is this normal?


Can you post a photo of the recovery tank?  A 2008 may use a different one than most members are familiar with.  The 2006 and earlier units definitely had hot and cold levels clearly marked on the tank.
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

Re: Coolant Question

Reply #3 –
Quote from: Michelle –
Can you post a photo of the recovery tank?  A 2008 may use a different one than most members are familiar with.  The 2006 and earlier units definitely had hot and cold levels clearly marked on the tank.

Yes. I will tomorrow before a short trip to Arkansas. I'm confident that the radiator is full since coolant started to leak as I loosened the radiator cap on a cold engine. I was just puzzled from a car and light truck perspective to not have coolant in the recovery tank. My first MH and my first big Diesel engine. Probably a lot of stupid questions coming. But like a ground school instructor told me going through 777 training. The only stupid question in my class is the one you didn't ask. 😊
Thanks to all for your patience.
2008 Nimbus 342
Build# 6464
ISM 500
Allison 4000 w/retarder
2021 Jeep Grand Cherokee

Re: Coolant Question

Reply #4 –
Quote from: Res777 –
Yes. I will tomorrow before a short trip to Arkansas. I'm confident that the radiator is full since coolant started to leak as I loosened the radiator cap on a cold engine. I was just puzzled from a car and light truck perspective to not have coolant in the recovery tank.

There should definitely be coolant in the recovery tank.

Most newer coaches (2003 and newer) like yours should have Extended Life Coolant (ELC) in them.  This avoids the "flush and fill" routine for a number of years, and the coolant can be tested if the correct strips for the particular coolant are used.  (given it's a newer coach, the whole discussion of OAT or not OAT coolant should not apply)

Reasons for lack of coolant in the overflow tank could be microcracks in the overflow tank itself, air pocket when the coolant was last changed, and a poor seal/incorrect type of radiator cap (you need a recovery-style one).  Have not seen a recovery tank that lacks Hot-Cold line level clearly marked, though.
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

Re: Coolant Question

Reply #5 –
Check closely.  It may be molded into the tank and you can find the hot/cold marks, even if they aren't a contrasting color.  I used a magic marker to make mine standout.

Rich
Rich and Peggy Bowman
2002 U270 3610 WTFS, build #5939--"Freedom"
2022 Jeep Grand Cherokee Summit 4xe
SMI AirForceOne brake system
PakCanoe 15

Re: Coolant Question

Reply #6 –
If you know what coolant is in there, add that (50/50 with water unless pre-dilute).

But, if you don't know what is in there, just add distilled water.  A quart or two won't significantly change the concentration and is better than combining what may be two different types/chemistries of coolant.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Coolant Question

Reply #7 –
I would be more interested to know why the dealer sent you down the road with an empty overflow tank if you paid to have it checked.
1994 U280, Build 4490
Deming, NM.

Re: Coolant Question

Reply #8 –
It is possible that the coolant level was good when he left MOT and there is a leak.  The engine then sucked the overflow bottle empty as it cooled.

Rich
Rich and Peggy Bowman
2002 U270 3610 WTFS, build #5939--"Freedom"
2022 Jeep Grand Cherokee Summit 4xe
SMI AirForceOne brake system
PakCanoe 15

Re: Coolant Question

Reply #9 –
Robert,

Unless you are the original owner of a motorhome, you should never expect the coach to be in original factory condition.  Pre-owned coaches are often "modified" by previous owners.  It is possible that the coolant recovery tank in your coach is not the one installed at the factory.  Not that it really matters - any translucent plastic jug will suffice.  it should hold roughly a gallon of liquid.  If it lacks "high" and "low" marks just add your own with a indelible marker.

Photo below of the factory tank in our '93 U280.  Probably not exactly the same as what was factory installed in your coach, but it should have been something similar.  On my tank, the hose from the metal radiator reservoir is connected to the bottom of the recovery tank.  Recovery tanks can be designed with the IN/OUT hose entering the tank from the top or from the bottom.  Either way works fine.  Note also that to utilize the recovery tank you must have the correct "return" type cap on the metal coolant reservoir.  See diagrams below:

Link to a recent thread on the topic of radiator caps:  Radiator cap


1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Coolant Question

Reply #10 –
I was finally able to see that the marks are there with a flashlight. Very difficult to see. I will certainly be taking a permanent marker to them. Checked it while it was hot after running on the interstate today. In our lovely Texas Summer weather. 99 degrees. The tank level was about at the cold mark. So I guess maybe a little low.
Thank you all for the help.
2008 Nimbus 342
Build# 6464
ISM 500
Allison 4000 w/retarder
2021 Jeep Grand Cherokee