Community Forums

robertj1979 · 09-30-2020, 07:45 AM

Anyone have any issues with coolant loss on Maxxforce 10?

I have had to add about a gallon of coolant to the recovery tank on two occasions in the last 6 years. When the coolant level gets low in the recovery tank, you get a "STOP Engine" flashing red light along with the normal yellow Regen light. It will de-rate and ultimitely put you on the side of the road. There is a sensor in the recovery tank. Last time I added coolant was about two years ago. Last trip I had to do it again and all seems ok but wondering if this is normal or could be a problem? Checked oil and level has not increased so no coolant is getting in the oil or would have noticed. Also checked for obvious leaks with none noted. Will have it tested soon when radiator system is flushed but strange how it randomly seems to loose some coolant over time. Last trip I got into some stop and go traffic for quite a while but not sure if it could be somehow related.

36PFT · 10-01-2020, 08:47 AM

Hi. We had 2 very small leaks. It was loose hose clamps. One at top/front of the engine (have to remove closet hatch to get to it), and the other was at the thermostat that is behind the air filter and below the alternator. I just tighten the clamps and all is good. Stanley

Traps90 · 10-01-2020, 10:27 PM

We have had to add around a 1/2 gallon every year since new (6,000-7,000 miles per year average). Not sure where it was going. Never could find where it leaked anywhere. Never did get any worse.

robertj1979 · 10-02-2020, 11:11 AM

I discovered we have a leak. Was not showing up until I added the coolant needed to replenish the recovery tank. I ran the engine and no leaks were noticed. After sitting a couple of hours noticed dripping coolant from the thermostat/connection near the alternator. No noticeable damage to hose but definitely dripping from that connection. It is difficult to reach that area from underneath or behind the air filter canister. May take to repair shop because need to flush radiator anyway. Must be a common problem. Wondering how Stan was able to reach the thermostat? I am too large to squeeze in that area behind the exhaust pipe but my wife said she may give it a try. Thanks for response.

36PFT · 10-03-2020, 08:49 PM

Sounds like the factory did not properly tighten your clamps either. I used a long 1/4" ratchet extension and a swivel 5/16" socket. Got it past air filter housing and gave it a 1/2 turn. That was 3 years ago. This spring the thermostat chafed (brass housing) in the bracket, and started to leak. Had to remove the air filter housing to gain access. Drained radiator, removed thermostat and soldered the hole. Have gone 9500 miles, no leak. Stan

robertj1979 · 10-04-2020, 09:19 AM

Thanks Stan. Still deciding if I am going to repair it myself or take to the shop because need to get transmission serviced also.

robertj1979 · 10-07-2020, 02:22 PM

Took Motorhome to authorized MaxxForce Service center. They let me know that the part leaking is not a thermostat but a "flow control valve". It is definitely the fitting close to the alternator behind the air filter housing. They also said that they are unable to locate a replacement part but are working (two days now ) to locate one. The plan now is to take it apart and see if they can find a suitable replacement part at an auto parts store. Looks like this is turning into a bigger deal than I thought.

36PFT · 10-08-2020, 06:25 AM

Wow. I guess the technical name is flow control valve. That way they can charge extra. Is that not what an engine thermostat does? In this case it helps the engine warm up faster. Please keep us posted. Thanks Stan

robertj1979 · 10-08-2020, 02:22 PM

Just got the estimate from Rush Truck service who is an "authorized" Maxxforce repair station. Was told the part is not available and not a Maxxforce part. Was advised that the coolant system is exclusive to the motorhome and not the same used on their trucks and replacement part is not available. They said they can repair with an alternate part but estimate was very expensive in my opinion. I requested estimate for Coolant flush/repair of leak and transmission replace filters and fluid. Estimated cost from them is $2160..about $1000 higher than I expected.

36PFT · 10-09-2020, 08:46 AM

Any idea what part they are talking about? Is it available from REV? Stan

robertj1979 · 10-10-2020, 10:54 AM

Not really. I know it is the thermostat/ flow control valve located near the alternator but their parts guy could not seem to find it. Not sure where all they checked but will have an update next week.

robertj1979 · 10-17-2020, 09:49 AM

Motorhome cooling system leak was repaired by replacing the thermostat. Stan is correct they changed the name to flow control valve initially but it is a thermostat. Part number is 1887417C1 available from International Harvester and others. Found part on internet for around $250 but was charged $355 on work order. Seven days in shop and am sure Motor Homes are "low priority" as their truck business is first. Had cooling system flushed and transmission serviced and total bill was a little over $2300. In all fairness, the thermostat is in a bad location and spoke to the guy doing the work to repair. He said they were fortunate to have a "small guy" working there who could actually get to it and was difficult to access even after removing air filter housing. He stated that the coolant overflow tank is mounted in such a way that you can not access the lid easily and they had to remove the tank to complete the coolant flush. Apparently there is not a "radiator cap" on this system and all fluid is added through the overflow tank. According to the technician, if coolant level drops on this engine there is a problem. I suspect I have had a small leak for some time at the thermostat that got worse over time. Technician stated that they see quite a few of these engines leaking from this location so it is a common problem. Price for this work was "high" in my opinion but am confident it was done correctly and at least have some recourse if something goes wrong.

Also, unrelated to this problem but spoke with the technician about annual maintenance that I complete including oil and filter changes. He stated that he recommended "not" cleaning the filter screen in the fuel pump because of the risk of damaging the pump. I do change both fuel filters (primary and secondary) every year. He stated they rarely see any problem with the screen on the pump and damage to the expensive pump can occur if not done correctly and it is better off left alone. Cost of the pump can be around $600.

36PFT · 10-19-2020, 07:35 AM

Hi. Glad it was fixed. I thought the "flow control valve" was an International part. Remember, International was the company that owned Holiday Rambler when our coaches were made. My arms are just long enough to reach in with the air filter removed. I do not understand his comment about the screen in the fuel pump. You have to lift the pump from its housing (unplug connection and remove 3 screws ) and remove the screen ( snaps in place ). Mine has never been dirty. I guess if you drop the pump it would get damaged. I also don't understand the recover tank comment. When I drained my system to repair the "flow control valve" the overflow tank drained completely.Is you tank above the dip stick? Yes, you need a step ladder to fill it. Stanley

robertj1979 · 10-19-2020, 08:08 AM

I think he was just commenting on the electrical connections etc. with the fuel pump and the fact he rarely sees the screen dirty as long as the filters are changed. My recovery tank is mounted very high above the dipstick about two feet and the cap is almost impossible to access. The cap is actually at the very top of where the access door closes. Don't know why they would have built it that way but makes access almost impossible. Only way I could add coolant was to "snake" a very flexible funnel hose in there and have a fairly tall step ladder handy.