Overheating: 2003 Dutchstar/Cat 3126

[BearAndMoon]

We left home 3 weeks ago on what was supposed to be a 5 month trip. 90 miles north, to spend three weeks helping a friend do the continuing rehab of a house he bought that was damaged in the 2007 flooding of Centralia, Washington, then south to the central coast of California, with a stop over at a event we were to vend at, the last weekend of this month.

We did an oil change yesterday, and left Centralia this morning. We stopped for fuel in Woodland Wa. no problems.

We made a quick stop off to pick up supplies in Tigard Oregon and when we came off the free-way, the alarms went off: We were over heating. The coolant reservoir was full. The temperature was at 220+.

Could I still have low coolant levels, even though the overflow tank was full?
Thermostat issues? I was still getting hot air when I ran the heater on the dash, so the heater core is getting flow through it.
No oil in the water, nor water in the oil, so that pretty much rules out a head gasket, right?
It's a 2003 newmar Dutch Star, CAT 3126B with 54,000 miles on it.
The oil pressure is right where it should be.

We had no issues heading north three weeks ago, none until we got off the free-way this afternoon.

I don't want to cancel this trip, however if we cannot find an answer, we're stuck here for the winter. Not something I relish at all.

[wolfe10]

Brad,

Couple of things:

1. Once cooled down, remove the radiator cap and verify coolant level there-- with an overflow reservoir, it should be full (no air).

2. The 3126 has a separate V belt that drives only the water pump. Check its tension-- it is NOT on an automatic tensioner. If you have a rear radiator, you will need to lay on the ground, driver's side of engine (front of engine, back of coach).

3. If above OK, I would replace the thermostat(s). Not that difficult to do. Probably have two in the same housing. Go to a Caterpillar dealer with your engine serial number to get the right one(s).

4. If rear radiator, when was the last time the front of the CAC (Charge Air Cooler) was cleaned?

[DaveAtherton]

Brett, sounds like a stuck thermostat or one partly stuck. Coming off freeway so not under heavy load and

sounds like this just happen. Possible belt or idler pulley fails check first than thermostat. Dave

[dickandlois]

Brad, Good information already posted.

I have had a thermostat fail(the spring retaining metal hoop failed at the top) this allowed the valve to twist sideways. Almost a total blockage of coolant flow.

The thing failed suddenly, no indication of a cooling problem before hand.

Hope it is a simple and easy fix.

Rich.

[BearAndMoon]

Water pump belt is tight, pulley is functioning with no audible or visual signs of malfunction. I am now leaning towards the Thermostat idea.

What is the procedure for cleaning the CAC, Wolfe?

[wolfe10]

Brad,

Drain 2 gallons or so of coolant.

Access the top of the engine: under bed or closet-- you need to get to the top front of engine (back of coach).

The thermostats are under the top radiator hose. Pretty easy to get to.

Make sure you remove all the old gasket and USE A NEW GASKET.

Pour the coolant into the thermostat housing until just below overflow level (this prevents an air lock when starting the engine).

Install thermostats and gasket.

Pour remaining coolant into radiator/overflow reservoir. May not take all of it until engine started, warmed up and cools down.

[hermanmullins]

Brad,

One way to check the thermostat that you remove is a pan of water. Take a saucepan put the thermostat in the pan and cover it with water set it on the stove on high. As the temperature rises watch to see if the thermostat begins to open. If it opens all the way before the water boils then it is good (if you have a thermometer in the water you can confirm at what temperature it opens). If it only opens partially or not at all then it is bad.

This might help you know if it was the problem or not.

Hope that is the problem and you can keep it cool.

Herman

[wolfe10]

While the "heat in a pan" test will sometimes tell you if a thermostat is good/bad, there are times when it is just starting to hang up and the "trauma" of removing it will make it perform properly, but will hang up again when reinstalled/reused.

Thermostats are just not that expensive-- if you are going to the trouble to remove, just replace them.

[hermanmullins]

Was not suggesting to use the old one if it does open. I never go into replace something and not replace a component in there. Such as in this case if I go in to replace the thermostat I will also replace the radiator hose and clamps. To me that just makes sense.

All I was suggesting was IF Brad wanted to, this was method to test the old thermostat.

Herman

[wolfe10]

Brad,

Cleaning the CAC/radiator: http://forum.dieselrvclub.org/index.php/topic,6601.0.html

[BearAndMoon]

Well, That went better than expected.

We ordered parts through the local Baxter auto parts, because they're just a quick walk down the street. They failed to get them.

This is the second time, in two separate locations that this company has let me down on ordering parts. I won't do it a third time.

We decided to go straight to the local Caterpillar dealership here in town. It's quite a way across town from us, but well worth the trip.

I want to give a big THANK YOU to the great folks at Peterson Caterpillar of Portland Oregon. Both Mark and Nick in the service department went above and beyond expectations.

Mark got us home with his help over the phone when we were stuck on the side of the road. Nick texted back and forth with me as I went through the repairs, had me text pictures, and made the job go smooth as silk!

Finally, Tim, in the parts department. His help was incalculable. He got me straightened out on what parts, and what coolant we needed, and gave me the time to ask innumerable questions, taking time away from the lunch his company had bought its employees today.

This is a fantastic company to work with. I was warned by several people that I should avoid the Cat engine if possible. Peterson Cat. made me glad I chose this coach. If I have to work on it again, these folks will make my job that much easier.

After we had everything put back in working order, we started up the engine and let it run. It took 20 minutes to get up to 195 degrees. for the next 20 minutes it sat at that temperature, never wavering. That wouldn't have been the case day before yesterday.

The folks on this forum were also a great help. I wouldn't have thought of filling the coolant up to just below the thermostat housing lip if not for Wolfe10.

We did test the old units. one was most definitely bad. Replaced both.

You folks were right, that old gasket did not want to come off.

A full system flush and then refilled with a 5 year 150,000 mile extended life coolant, per Tim at Cat.

We go out for a test run on Sunday, wish us luck.

We may just get to San Jose Ca. by the 25th as planned!

[DaveAtherton]

Bear and Moon, Glad you had a good experience with Peterson Cat, Starting reading your post about going

down to local parts store for thermostats, hope you understand Cat Dealers whether you like them or not , Cat will

have the correct part made for Cat engine that was made by Cat spec's. You have a very high dollar engine

with what is called a heui system, going low road on oils and parts will cause many problems ahead. Again glad

to hear Peterson Cat came to your call. Dave Atherton Retired Cat Mechanic

[rickey0640]

I had the same problem It turned out to be the Fan controller. It easy to change.

[oldrick38]

I had a very similar problem I took it to Frightliner in Gaffney South Carolina. They determined that it was a clogged radiator, they actually have a steam cleaning station there and they steam cleaned the radiator and I have never had another problem with it. From what they told me this is a common problem with a rear radiator.

[v35pilot]

Had same problem on 04 Meridan. Tried everything that is talked about here.

We to CAT dealer and his first question was " has the slobber tube been modified"?

WHAT THE **** IS A SLOBBER TUBE?

He explained on CAT engines up to year model 2007 the crankcase breather was a tube that hung

below the engine. The venting oil fumes accumulated on the rear facing radiator and caught dirt build up that blocked the cooling fins.

He said get so Simple Green Full strength and spray on both sides of radiator and let set 30 mins.

Then flush with low pressure fresh water.

I then added a Long hose to the slobber tube so the fumes would exit behind radiator and secured with hose clamps.

I did this twice and never had an overheating problem.

[oldrick38]

I forgot to mention that they also extended the slobber tube. Frightliner also said this is a common problem and causes the blockage with a rear radiator in most cases.

[bomarhe]

I recently had the same symptoms on our 99 Endeavor. The reservoir is just that, it's for expansion, not to fill the cooling system. As mentioned earlier, remove the radiator cap and physically check the quantity. Mine was very low. Added water and bingo, no more bells. It does sound like you had a different issue/solution. Just food for thought.

Bob