I am sure you folks will give me more ideas on what is going on with this issue. I have replaced the entire cooling system on this 440 and added two 12" electric fans in conjunction with the regular fan and new fan clutch, 180 thermostat, new high flow water pump, radiator was dipped and cleaned and I reflushed it 4 more times. No kinks in any hoses or any problems I can see and you can see the water pumping the fluid great.

I have been in the mechanic business for 25 years. That being said, I am always learning new things and if I don't know I will ask others for their ideas. I might be missing something here but I don't know what.

Now to fill you in with the big picture. Motor and heads rebuilt by a machine shop and has 800 miles on it at this time. Put everything back together and was noticing the temp on the higher side (not boiling). That is when I started changing the other parts that were not new like fan clutch, thermostat, waterpump and when that did not satisfy me I added the two 12" fans pushing through the radiator. I also flushed for the 4th time  the motor and radiator when the waterpump was off and radiator hoses were disconnected.

I drove it 80 miles to go camping and it did alright, no boiling just on hot side of gauge. I drove up to 65 mph and it was climbing to the boiling point so I slowed back to 55 and it cooled back down. I sped back to 65 and temp climbed again so back to 55 and it cooled down again. I pulled over every time it started to get on the hot side and ran out with my laser thermometer to check the temp exactly. The hottest I could read was 225 at the top of the radiator and the rest of the radiator was below but around the same temp, so I know the radiator is not plugged.

I have read on the internet that some times newly rebuilt motors will run on the hot side until it is broke in all the way. I have never experienced this issue and I do not know if it is true, but I did read that on more than just one site. I have changed the break in oil after 500 miles with more break in oil. After 1000 miles total I will change to regular 10W30 oil and see if that will help but that does not seem like it would make it run cooler.

Am I missing something here that you can tell? You can read how much I have replaced and to me I can't see why it's running on the hot side.

Views: 170


You need to be a member of Good Old RVs to add comments!

Join Good Old RVs

Comment by Jimco_W001 on June 10, 2015 at 7:48pm

Evans coolant is a great product.Getting rid of the water stops freeze ups,rust and it has a boiling point of around 400 F.It also reduces engine preignition.Plus no pressurized cooling system needed.But your cooling system should work without it.

Things you can check. Is the radiator fan.Is it turning in the right direction?Does the thermostate open nice and fast when put in boiling water?Are you sure your temp gauge is working right?

Comment by Rich Thomas on June 10, 2015 at 7:34am

Dwayne, If you would happen to try that Evens coolant I would be interested in the results. I want to put a bike rack on the front of my C class but hesitate because of airflow to the radiator and think that stuff may be the answer for my application. For health reasons I can't really ride the bike enough to justify  the expense of either. LOL I keep hoping that will change though and I keep it around for incentive. 

Comment by Dwayne on June 9, 2015 at 10:41pm

I thank you all very much for your incite. I am thinking the same as  Lakota Wolf at this time. I have added water wetter with no success. I will check into the other coolant types too. Thank you

Comment by Rich Thomas on June 9, 2015 at 8:32pm
Dwayne, the coolant I was suggesting is Evens water-less coolant. you can google it . pretty interesting stuff. good luck with what ever you try hopefully it's just a tight engine after rebuild.
Comment by Jim Stoltz on June 9, 2015 at 8:22pm

When our old RV ran hot my dad would turn on the heat.

Comment by Jim Stoltz on June 9, 2015 at 8:22pm

Defrost on warm? More capacity. Running water through the heater core.

Comment by So ska noname on June 9, 2015 at 8:20pm
Oh, I turned on defrost and it cooled down. Why? I don't know.
Comment by So ska noname on June 9, 2015 at 8:19pm
New thermostat on my old ford truck runs hotter than old one. Is your over flow working correctly? My mechanic said my rebuilt engine had to be broke in? On big hills(Wyoming) truck ran hot. You have a transmission cooler? My knowledge limited.
Comment by Lakota Wolf on June 9, 2015 at 8:15pm

With a big block, (as yours 440), The Rings have to break in and the valve guides have to wear in, thus creating a run hot scenario. I did a rebuild of my 5.9 Dodge,,, I had the same exact issue. My Mopar friends was even baffeled.. We double,triple and triple checked everything,, even messed with the timming numerous times. An old school guy walks over and said,, boys,,boys,, its physics. Fresh rings on a fresh bore, have to wear into place. I was a bit skeptical because I have rebuilt chevys and dodge small blocks and never had a run hot issue. He said its inherit for the big blocks to run hot. 

I would suggest that ya recheck the timming and make sure the CHOKE is operationg properly (if Carberated).

Comment by Jim Stoltz on June 9, 2015 at 8:13pm

I've used Water Wetter with some success, but it sounds like you have a capacity issue. As in the radiator is not capable of transferring enough heat at speed to maintain the temps. I have the opposite problem with my 454. It will get warm in traffic, but if I crank up the RPMs it will cool down immediately (with the help of the clutch fan). It will also get warm climbing hills, but the faster I go (more RPMs to move coolant through the radiator) the cooler it will get.

If you don't have overheating problems at idle, I would argue that your electric fans are pretty much just a restriction at speed. They're blocking air flow through the radiator. When I was young we had a mid-70s Winnebago with a fresh 440 in it. It would get hot, too. Aftermarket electric fans didn't exist at the time. My dad put a stainless steel, flex-blade fan on it and that seemed to help. Some baffles to direct air through the radiator rather than around it would help, too.

Just some ideas....I'm a tinkerer not a legitimate mechanic :)



  •         How To Links 

-Search Good Old RV's

-Start a New Group 

-Roof Repair Photos & Products

-Repair an RV Roof

-Pick Roof Sealer   

-Understanding RV Electrical Systems 

-Get RV Insurance   

-What to Look For When Buying a Used RV

-Jack Installs Fuel Injection in his Dodge 



 Artist Roads                                              



If you love classic and vintage RVs then come Join us. Come on in and have some fun. JOIN HERE NOW


refurbishing vintage RV paneling

Started by Larry Curfman in RV Repair & Maintence Sep 15.

Carb not getting gas 1 Reply

Started by Paul in RV Repair & Maintence. Last reply by Paul Sep 14.

Painting an aluminum trailer 1 Reply

Started by Judy Norton in RV Repair & Maintence. Last reply by Judy Norton Sep 9.

Blog Posts

Anyone got a manual for my camper ?

Posted by Pacy on September 21, 2021 at 10:17am

Anyone know what year this Corsair could be.

Posted by Jay M Ball on August 22, 2021 at 6:24pm — 1 Comment

1973 Dodge Diego Anthony Motor Home Restoration Plans

Posted by Kevin on August 15, 2021 at 11:52am — 1 Comment

Quandary about tire pressure

Posted by CH Smith on May 19, 2021 at 5:43am — 1 Comment

Third time is a charm!

Posted by S.Heins on March 31, 2021 at 1:14pm



  • Add Videos
  • View All


If you love classic and vintage RVs then come Join us.

 Come on in and have some fun.      

 Dedicated to a simpler, more rewarding and fun way of life in a Good Old RV... 

Vintage Travel Trailers, Vintage Campers, Camper Restoration, Bus Conversions, Vintage RV Forums, Old RVs, Tiny Homes, Boondocking

A work of art by member Paige Bridges


 Disclaimer - Please Read it

Enjoy this site and use it totally at your own risk.

By using or viewing this site YOU agree to Hold Harmless anyone associated with it including other members. Also, YOU agree that YOU are solely responsible for ANY and ALL actions, results or damages. Members "opinions" are just that and any repair or alteration comments or recommendations are by folks who are not licensed repair  or mechanical professionals. Any repairs or modifications you do totally at YOUR OWN RISK. Use licensed professionals for all work to avoid possible serious injury or damage. Use  banks for purchases.  Have fun!

Copywrite & Trade Mark Registered GoodOldRV© ,GoodOldRVs©, GoodOldRVs.com©,GoodOldRVs.net©,GoodOldRV.Com©

© 2021   Created by Russell E Johnson.   Powered by

Badges  |  Report an Issue  |  Terms of Service