Over Heating of 330 3126

[motojavaphil]

We were in Bullhead City last summer. We left in 110 degree heat and were going to I40 which was a very long hill. On the way up the buzzer and gauges indicated over heating. We stopped and it cooled, and this was repeated several times going up this hill. We got to Williams and found the tranny down 2 quarts and the coolant down as well. I was surprised at this as we had serviced the rig six months prior. Everything was topped off and there were no further problems. We took another trip to Corpus in December/January and had no problems although winter temps would have a positive effect.
We are preparing to go fulltime up to SD and then out to OR. I have changed oil, lubed and made sure all fluids are where they should be. We pressure washed the radiator. I am wondering if there is more we should do. I was wondering about the radiator cap, shows 13 psi rating. Does this sound right? I was going to take it to a shop to have the radiator pulled and cleaned. Is this overkill? It is a 10 year old system with 26,000 miles on it.
Sure appreciate any advice.
Phil

[sgtjoe]

Phil, I have a 300 3126 in my mh and it is on a Freightliner chassis. There was a Service bulletin on mine about the short oil blow by tube that caused the radiator to plug up and overheat at 15,000 miles. Mine is a Tradewinds. To see if it is clogged up have some one run a flashlight completely around the radiator from the rear while you are looking at it from your access panel in the inside rear of the mh. Do this when it is really dark outside. If you can see the light all the way around it is not clogged. If it is clogged use Dawn dish soap in a spray bottle and spray the inside and outside, make sure you get the outer corners of the rad really good on the inside, you may have to spray from under the mh. Let it sit for a few min and then use a hose to wash it down from the outside and inside or under it. Do not use a pressure washer unless you are sure you won't be bending the cooling fins. BTW, it cost over 750.00 to pull my Rad and other things to have it steam cleaned. I now have a hose that sets a few inches off the ground, great conversation piece.

[ldsord]

Like Joe said,a clean radiator is the secret,I had to spray mine 7 times.I crawled under and sprayed de-greaser into the fan with the motor running,then used a spray nozzle on the hose inside and out,then extended the blowby tube.That fixed it.

[Kerry1956]

I have a Tradewinds with a 3126 that overheated as well. Mine had a few issues. The radiator cap was bad and didn't vent properly. The thermostat was too cool and never closed, and, the blow by tube wasn't extended. I did all of this but in addition, keep your RPMs up above 2000 when going up steep grades or mountains. The only air going over your radiator is what your fan pushes over it. Lugging these engines or letting the RPMs drop too low will get 'em hot pretty quickly.

[autofish]

This type of over heating can also be caused by a failed thermostat. The 3126 cat motor uses two stats that should be changed as per the service manual. One failed stat will cause up hill over heating. Let us in on what you find out ------------good luck.

[mycoolbeans]

On 8/19/09, I asked a question in the cat forum section and received a number of replies regarding the overheating. Advice was clean radiator with simple green solution from underneath toward the CAG and from the front, let the solution sit for 30 minutes, gently rinse from both ends with a garden hose (not a power sprayer). This worked wonders. You can do this and save money. Check the replies I received. I think they may help you. Also (if you have a Freightliner chassis), a call to Gaffney customer service will help. There is a lot of info out there....check Caterpillar customer service also. This has been a problem for many with rear engine radiators.

[embmac]

When towing uphill, don't let your rpm's get above 2000. Maintain the speed you want with the trans, but stay between 1500/2000 rpm.

[motojavaphil]

Sorry I have not gotten back to the thread. Traveled over the summer in different temperatures and terrain. It did get hot in a few places and I did keep it above 2000 RPM in those areas. Also changed out the radiator cap. We did not over heat but I felt it would have if we repeated the conditions encountered at Bullhead City on the way to I-40. I am taking it in tomorrow and having the radiator steam cleaned. I am going to put this issue to rest once and for all. The tube had been moved but as Jim Statkus explained it still puts a mist out there that plugs the radiator over time. We are putting a box on the end of the tube to collect the blow by.
Moto

[motojavaphil]

We took the rig in on Monday. The radiator was taken out and steamed. The inter-cooler was also removed and steamed. Jim Statkus stated we had 25% cooling. I had soaped and sprayed the radiator and cleaned as best I could from underneath. He not only found the blockage, but beyond the usual crud there was grass, lots of grass! A lot of it was between the inter-cooler and radiator where no amount of spraying could clean it. The tube has a collector on it for catching the evil mist. Its not cheap but I suspect well worth it. It's amazing me that all of this could happen within 30,000 miles that could destroy an engine capable of 10 times or more that distance.
Moto

[Vegasdan]

I had to replace my surge tank in Jan and they found my 3126 radiator was partially plugged. They cleaned and all is good now. I know the 6% 8 mile climb out of Bullhead City towards Kingman will be the ultimate test in the summer time.

[motojavaphil]

Since the cleaning the temp has not gone beyond 194 degrees on a long hill. Transmission is cooler too! We will be driving in 90 degree weather tomorrow with a few hills. I'll post results.

[ninos]

When you guys say overheating, what is the temperature that the cat c7 should run? what is the hotest temperature that this engines can go up to with out overheating, The most I have seen mine was at 201 for about 5 seconds up hill towing a heavy 22 foot in closed trailer loaded with bikes, but the 201 temperature was just for a couple seconds and the rest of the trip was always between 185 and 195, Is this a ok temperature? thanks to all, Joe.

[motojavaphil]

Joe,

I think those temps are awesome. We did get on a long hill with a headwind in 90+ temps and saw 200 degrees after the cleaning. Much better than before. Your temps are healthy from my non-expert perspective.
Moto

[OneRVer]

Quote:

Originally Posted by ninos When you guys say overheating, what is the temperature that the cat c7 should run? what is the hotest temperature that this engines can go up to with out overheating, The most I have seen mine was at 201 for about 5 seconds up hill towing a heavy 22 foot in closed trailer loaded with bikes, but the 201 temperature was just for a couple seconds and the rest of the trip was always between 185 and 195, Is this a ok temperature? thanks to all, Joe.

Hello. New to this site and you all have already explained my overheating problem with my 3126. Anyway, my manual states that my temperature should be in the range of 190 to 215 degrees. Never exceed 230 degrees. Your motor may have a different range I am just stating what my manual states.