Coolant Change And Temp Won't Go Up Beyond 155F

Topic: Coolant Change And Temp Won't Go Up Beyond 155F (Read 675 times) previous topic - next topic

Coolant Change And Temp Won't Go Up Beyond 155F

September 28, 2016, 12:01:01 pm

I flushed my cooling system twice and then added the correct amount of coolant concentrate and distilled water.

Each time I restarted the engine after filling the temperature wouldn't get above 155F. The heater will run hot, maybe not as hot as it should be running but that tells me the coolant has been circulating.

On the final fill I left the radiator cap off and watched as bubbles appeared which I considered burping. When the coolant level increased with expansion and reached the edge of the filler neck I replaced the cap. Since then there has been no change (maybe
1/4" - 1/2") in the overflow tank.

Am I missing something? There's a braided line which goes from the metal coolant pipe (high part of the system) to the fill tank,
so I figured that it would bleed the air off if I didn't put the cover on initially. If it isn't completely free of air then how do I continue to burp it with the coolant coming out? Catch basin under the filler neck until bubbles stop appearing?

Re: Coolant Change And Temp Won't Go Up Beyond 155F

Reply #1 – September 28, 2016, 12:03:12 pm

Did you change the thermostat? Sometimes, flushing breaks loose something that jams the thermostat.

Re: Coolant Change And Temp Won't Go Up Beyond 155F

Reply #2 – September 28, 2016, 12:17:35 pm

Same thermostat.

But since my original post the engine temp is now at 175F and the overflow tank coolant level is half way between hot and cold.
The outside air temperature here is 74F and the engine is on fast idle, and I have alternated between the slow and fast idles during
the coolant change process.

Re: Coolant Change And Temp Won't Go Up Beyond 155F

Reply #3 – September 28, 2016, 01:53:26 pm

You will likely need to drive the coach to get the Tstat to open fully.

Re: Coolant Change And Temp Won't Go Up Beyond 155F

Reply #4 – September 28, 2016, 02:58:04 pm

If this occurred before the system has been "burpped" of the air pockets, quite likely there was air in the thermostat housing which on many engines is where the temperature sensor is located. VERY DANGEROUS, as coolant temperature can go very high in the head and even crack it. Air, even hot air will not open the thermostat and allow circulation.

Best defense when changing coolant is, after pouring in as much as you can in the radiator, remove thermostat and top off there before starting engine.

Yes, some cooling systems are designed with a bleed hose from thermostat housing to reservoir which does this automatically, but some are NOT.

Re: Coolant Change And Temp Won't Go Up Beyond 155F

Reply #5 – September 28, 2016, 03:17:46 pm

Quote from: wolfe10 – September 28, 2016, 02:58:04 pm

VERY DANGEROUS, as coolant temperature can go very high in the head and even crack it. Air, even hot air will not open the thermostat and allow circulation. Yes, some cooling systems are designed with a bleed hose from thermostat housing to reservoir which does this automatically, but some are NOT.

Damn good post, Brett! Everyone would do well to bookmark your comment and remember it. I wonder if the problems we hear about heads having to be replaced are directly related? Do shops still offer "magna-flux" to detect head damage?

Re: Coolant Change And Temp Won't Go Up Beyond 155F

Reply #6 – September 28, 2016, 03:33:29 pm

And, Mike this needs to be done on your coach any time much coolant is drained/any time an air pocket can be created in the thermostat housing.

So, for example, to change the thermostat:

Drain and catch 1-2 gallons of coolant.
Remove thermostat and clean off old gasket
Pour in coolant up to top of thermostat housing-- this is the important part
Install new thermostat
Pour remainder of coolant in radiator and if it all won't fit in the overflow bottle.

The other option (at least on the Caterpillar 3116 is to crack open the coolant line from the thermostat housing to the air compressor to bleed air there.

I have done it both ways. They are equal, but have to do it one way or the other, as air will NOT open a thermostat.

Re: Coolant Change And Temp Won't Go Up Beyond 155F

Reply #7 – September 28, 2016, 03:58:27 pm

Quote from: wolfe10 – September 28, 2016, 03:33:29 pm

The other option (at least on the Caterpillar 3116 is to crack open the coolant line from the thermostat housing to the air compressor to bleed air there. but have to do it one way or the other, as air will NOT open a thermostat.

The only plans I have these days, is to know as much about the 3116 as you do!

Re: Coolant Change And Temp Won't Go Up Beyond 155F

Reply #8 – September 28, 2016, 04:14:57 pm

I know it's harder on these engines but we would pump the coolant in from the lowest point , air would be forced to top.Some of
ours held 500 ,600 gallons.

Re: Coolant Change And Temp Won't Go Up Beyond 155F

Reply #9 – September 28, 2016, 04:28:37 pm

Quote from: John44 – September 28, 2016, 04:14:57 pm

I know it's harder on these engines but we would pump the coolant in from the lowest point , air would be forced to top.Some of
ours held 500 ,600 gallons.

Yup, but that would work ONLY if you have an air bleed at the high point. THAT is the problem-- lack if air bleed at thermostat housing which on some engines is the high point.

Re: Coolant Change And Temp Won't Go Up Beyond 155F

Reply #10 – September 28, 2016, 04:48:52 pm

as was said earlier, you need to drive the coach under load, not just fast idle to get it up to temp properly

tom

Re: Coolant Change And Temp Won't Go Up Beyond 155F

Reply #11 – September 28, 2016, 05:14:02 pm

Actually coolant (not oil, etc) should reach thermostatic temperature at fast idle. If not, likely the thermostat is not closing all the way.

Re: Coolant Change And Temp Won't Go Up Beyond 155F

Reply #12 – September 28, 2016, 05:45:16 pm

In the picture at two small hoses, one runs from the cylinder head to the coolant tank and the other one runs from the top of the coolant pipe to the coolant tank.

I thought these were for releasing trapped air at the high points in the
cooling system.

Re: Coolant Change And Temp Won't Go Up Beyond 155F

Reply #13 – September 28, 2016, 05:53:37 pm

Yes, unless there is a lot of air trapped in the thermostat housing, these two hoses should allow for air to escape to the fill tank.

Most written instructions on filling call for maximum of so many gallons per time-- i.e. fill slowly to that air has a chance to escape.

Re: Coolant Change And Temp Won't Go Up Beyond 155F

Reply #14 – September 28, 2016, 06:00:52 pm

The filler neck is located in such a way that a rapid fill is almost impossible unless the engine cover has had the Xtreme upgrade.

What about the thermostat gasket................reusable, or new one required?
If new one is it Foretravel OEM?

Re: Coolant Change And Temp Won't Go Up Beyond 155F

Reply #15 – September 28, 2016, 07:14:06 pm

Get your engine serial number and the CPL number and call a Cummins shop and tell them what you need, Use only a genuine
Cummins thermostat.

Re: Coolant Change And Temp Won't Go Up Beyond 155F

Reply #16 – September 28, 2016, 07:17:06 pm

Quote from: Bill Willett – September 28, 2016, 07:14:06 pm

Get your engine serial number and the CPL number

And be sure to get them directly off the engine, not the "Component List and part numbers" in the "box 'o manuals" which has been found to be wrong on at least one occasion.

Re: Coolant Change And Temp Won't Go Up Beyond 155F

Reply #17 – September 28, 2016, 07:29:35 pm

Cummins has my engine number deep in their system.

Whenever I need it I refer to one of their bills/work orders.

Re: Coolant Change And Temp Won't Go Up Beyond 155F

Reply #18 – September 28, 2016, 09:16:58 pm

In changing the coolant, I leave the filter loose and pour in the new coolant at the tank until it is running out the filter. Then I screw the filter down and complete the fill into the radiator tank to full and the over flow tank to "cool" and never had a problem. The air is bled out the filter housing. I did this also after changing the thermostats, which as it turned out , were fine.

Re: Coolant Change And Temp Won't Go Up Beyond 155F

Reply #19 – September 28, 2016, 10:03:02 pm

I vacuum fill my cooling systems. A venture hooked to shop air puts the system into a vacuum and then a hose is hooked up to suck coolant into the vacuum. if you cant create vacuum you have a leak. If you get vacuum you put the hose into the container and suck the coolant mix in. This allows you to fill the system with almost no air pockets and also no mess.

Re: Coolant Change And Temp Won't Go Up Beyond 155F

Reply #20 – September 29, 2016, 08:19:11 am

Quote from: its toby – September 28, 2016, 10:03:02 pm

A venture hooked to shop air

Venturi?
If so, can you explain with a picture?

Re: Coolant Change And Temp Won't Go Up Beyond 155F

Reply #21 – September 29, 2016, 07:29:49 pm

Putting in a topic for it.

Affiliate Notice