Low Coolant Light

[pulsarjab]

Our 2000 Diplomat with ISC engine has an issue with the low coolant light. When starting, it comes on then goes off after several minutes of driving. The light will come on while driving, then go off. The plastic bottle is full. Coolant temps are normal. Is the sensor located in the plastic bottle? Thanks for the help.

[F16fan]

This is a problem on all the older Monaco's.

Corrosion builds up over time on the in-tank metal probe. The probe is located on the top of the plastic coolant overflow tank. It will have 1 or two wires going to it. There are YouTube videos of how to clean it, but the problem will keep coming back. My group of Dynasty owners, have been trying to solve this problem for almost three years now.

If you go to Monaco's website for parts, you may be still able to get one. (Hit &Miss), but know that there are no aftermarket/OEM updated parts for the 1 wire probe. I bought the Volvo tank latest replacement probe, and it had two wire hookups. THIS WILL NOT WORK, no mater how you try to wire it. It has to match the CLA module installed on your coach.

Recently, I blew my engine up, due to not having real time low coolant monitoring. So I am amazed there are no permeant solutions for this problem!

Someone even experimented with changing diodes on the CLA circuit board with limited success. But the problem came back after 6 months.

So all the old pros here, please chime in with your suggestions.

This is the last warning light I have on my dash, I really want it fixed!!!

Kysor Coolant Level Alarm 1039-07058-01 Monaco (1).pdf

[John Haggard]

So sorry to read that the engine blew.

 

So where did the coolant go 🤔???

Did you see a leak of coolant ?

Did the engine temp start upward ?

[jacwjames]

The newest version of the original coolant tank on my 2002 Monaco Windsor that I replaced in ~2014 had multiple ports for the coolant sensor.  At the time venders were supplying a Ford 2 wire coolant sensor but only one wire was needed since you just were using the coolant to send a signal to ground.  I opted to just go ahead and use two wires but joined them together and connected to the original coolant wire.  It worked and in fact alerted me when road debris took out my radiator and I lost a substantial amount of coolant before I could get stopped.  I had to have the radiator replaced in 2015.  

The Ford sensor mounted on the side of the new tank about 2/3rds way down.  The Ford part number is XC4Z-10D968-AA and are still available.  This will not work on the old tank unless you have a port on the side. 

Veurinks offers the new version of the nylon type tank but also offers the metal for the same price. https://shop.findmyrvparts.com/searchresults.asp?Search=tank&Submit=

[F16fan]

Since the coolant light was on always since the used coach was purchased, the only way to monitor was to watch the engine temp gauge. On last trip attempt (In the middle of Texas summer), outside air temps were above 100. Since day one, the coach overheated anytime the temps were upper 90's, so I was very nervous and watching the gauge like a hawk..

15 minutes after departing, the overheating began. Dash temp gauge reached 215ish, so pulled over, and let cool down. Checked coolant, and due to a bad gasket on the coolant overflow, some coolant was present in the engine bay. Topped off. For the next two hours, had to pull over two more times and repeat.

Then once I was in the very hilly portion of north Texas, temps started coming up agian. There was no safe place to pull over, so I pressed on cautiously. Then the temp gauge surged to 225, and I was panicking, looking for an exit or anything safe to pull over. Then temp kept climbing, and in an instant, the temp went to zero, smoke started pouring out of the engine bay, lost all power. Coasted into an exit, but the damage was done. All coolant was all over the entire engine compartment, and overflow was bone dry.

The result, being stuck for 4 weeks. Found a used engine, and was towed to Cummings in Amarillo for the engine swap. Thought I cracked or warped the head, but turned out it scored all piston sleeves, cracked the exhaust manifold, etc. On way back from engine swap, it all started agian. But outside temps at night came down to middle 80's, and I was able to get back home.

Turns out, my cooling stack (Radiator/Tranny cooler, CAC/HYD cooler) was completely clogged. Tried to clean, but it was slid grease and gunk. On removal of the cooling stack, I determined the root cause was the HYD fan motor O-ring failed, and dripped slowly out, over many years and clogged the inside of the radiator.

Repaired/replaced everything. In doing so, I determined the Fans Blades were  wrong for the direction of rotation!!!!! My fan was trying to blow air to outside of RV! And because the blades were wrong, it really overworked the fan motor.

Long story short, over $15K in repairs (And this is cheap, due to used replacement engine, and I performed cooling stack restoration on my own.), just because my low coolant light did not work.

 

So please, some find a permanent solution, before this happens to the next guy.

WOW!!!!

Thank you for your info jacwjames!

I will look into this right now!

I did not see the plastic bean shaped Volvo tank with the sensor on side on the link, so I think the 02 Windsor is different than the 97 Dynasty.

But all that maters is that the metal tank will directly bolt on, in original location. This is what my stock installation looks like. (See pic)

[vito.a]

Just remove the aluminum probe and clean it with Scotchbrite or steel wool.  It helps if you have two probes as you can always have one ready to go.  

We put a new probe in the lathe and bored a hole up the center.  It still needed cleaning periodically. 

Just be caerful not to overtighten the probe or the bottle will crack. 

Edited February 18, 2021 by vito.a

[F16fan]

Vito is correct. This is the temporary solution, so many of us have tried.

The problem is, if you are disabled, pulling the cooling tank every 6 months to swap out probes, is problematic. Doing the same repair over and over is not a solution. With the metal tank that jackwjames has suggested, if nothing else, it would make it more convenient, if the Ford probes have the same problem, because you would not need to drop the tank to get to the probe. The probe is on the side, so need to drop the tank just to maintain the probe.

And if you get in the habit of having the light come on, it renderers the warning system useless! When that light comes on in a properly functioning system, YOU PULL OVER IMMEDITELY!!! If the light comes on, and your first thought is...Well I guess its time to service the probe agian, you may not take it as seriously as you should, and wait for the next time to conveniently check the level, instead over pulling over immediately.

Please more experts chime in with your thoughts. Has anyone else switched over to the metal tank and Ford probe? If you have a new Ford probe, how long will it last before, repeating the work around Vito has mentioned? Once I fix it, I don't want to have to any problems for several/many years.

 

[lake49068]

I've never owned a side radiator coach so not sure if I'm barking up an incorrect tree but...don't the cooling fans on motorhomes always blow "out" from the engine compartment?  

Adam

2010 Neptune 37PBQ

[John Haggard]

Wowwww 

Sombody realy messed up your coach if youhad all those issues.

Fan blades

Dirty radiator 

Plugged cooling tower.

Leaking hydraulic motor.

Your lucky you ran as long as you could with no good and thorough servicing.

[Guest Ray Davis]

34 minutes ago, lake49068 said:

I've never owned a side radiator coach so not sure if I'm barking up an incorrect tree but...don't the cooling fans on motorhomes always blow "out" from the engine compartment?  

Adam

2010 Neptune 37PBQ

 Rear radiators blow out the back and side radiators suck in or that's what they are supposed to do.

[jacwjames]

36 minutes ago, lake49068 said:

I've never owned a side radiator coach so not sure if I'm barking up an incorrect tree but...don't the cooling fans on motorhomes always blow "out" from the engine compartment?  

Adam

2010 Neptune 37PBQ

Mine blows out, picks up cool air from under the coach.  I think it helps to keep engine compartment cool also. 

[F16fan]

John, You are right, the coach had a lot of problems. The repair list started at over 100 issues. It is now down to just 15 items! (Mostly interior)

Ray is correct, that is what most of the info online says.

Jacwjames, Are you sure? Just when I think I am figuring this stuff out, another curve ball! What direction does your fan spin if you are at back of the HYD fan, looking toward the radiator? Do you have the 1 or 2 fans? Maybe the 02 Windsor is completely different than 97 Dynasty.

[ktloah]

Source Engineering in Oregon has these sensors. My 04 Dynasty has the 1 wire probe and Jim hooked me up. He makes his own! Installed it in one of his new coolant expansion tanks and all is well

[F16fan]

Ktloah, Holy Crap!!!!!!! After 3 years a solution! You rock!!!!!!! Do you have the part# and cost? How long has it lasted without giving a false reading? Are their tanks metal, and bolt right into original location without modification?

Now the question is, is the 97 and 04 Dynasty coolant overflow tanks the same? Is it located in same location? (left side of engine bay)

Sorry for all the questions, but this is very important to me and several others!

[jacwjames]

The coolant tank shown in the 1997 Dynasty photo must be the volvo type tank.  I have no knowledge of this tank and it's performance.

My original tank was similar to the one shown in the Veurinks link but it was made out of a different type of plastic that over time of expansion and contraction would crack.  When I first bought my coach in late 2008 I had several small weeping spots that I patched using gorilla glue, this lasted about 5 years until I finally replaced with a nylon type (I think) tank.  At the time I purchase it from Guaranty RV, slightly cheaper).  I bought the coolant sensor from EBAY and the fittings from Lowes. 

I am going from memory on the direction of the fan air flow, next time I start the coach I'll try and remember and check, I could be wrong (wouldn't be the first time).  Maybe someone else can comment. 

Here are a couple pictures of the new tank and sensor that I installed in 2014.  Originally it was a one wire sensor.  The Ford was a two wire sensor so I just attached 2 wires and then jointed them to the original.  I did seal the end of the sensor with silicone.  I have not had a problem with the sensor giving me a false reading and it seems to be compatible with the low coolant alarm gizmo. 

[ktloah]

Talk to Jim @ Source Engineering...phone # 458-207-9442. He and his workers all worked at Monaco. He'll hook you up. I installed his home-made coolant sensor and it works flawlessly.. the tank bolts right up to the old holes. Take note of where your sensor is mounted..some are mounted low or high, left or right...good luck

[96 EVO]

5 hours ago, jacwjames said:

The coolant tank shown in the 1997 Dynasty photo must be the volvo type tank.  I have no knowledge of this tank and it's performance.

  memory on the direction of the fan air flow, next time I start the coach I'll try and remember and check, I could be wrong (wouldn't be the first time).  Maybe someone else can comment. 

 

Unless your hyd lines somehow got reversed, I'm going to say your fan pulls the fresh air thru the grill, and radiator stack.

[Romeo84]

I know these are two different topics but now I'm intrigued. I always thought the fan pulls in through the side and out the back. Seems like if it pushed out the side radiator it would be fighting wind resistance and dragging hot air over the block.  

[96 EVO]

3 hours ago, Romeo84 said:

  I always thought the fan pulls in through the side and out the back.    

They do.