Motorhome & Recreational Vehicle Resource

Since 1996

Search RV-Coach Online

Email Author email Troy  Reply to Message reply to message  Post New Message post new message      search forums
All Postings that advertise items for sale will be deleted from the Discussion Forum. You may post sale items for free in the Classifieds section. Sign up now.
All Messages in ThreadAuthorDate
78 Dodge 440 overheating Troy 8-1-02  
I have a 78 Dodge class c with a 440. My problem is when at idle the temp slowly climbes. As soon as I start moving or I increase the rpm the temp slowly comes back down. It hase a 18 in heavy duty 7 blade flex fan, new thermostat, all the belts are tight.
Re: 78 Dodge 440 overheating Joe 8-2-02  
Did you install the flex fan and thermostat to correct an overheating problem? Is the shroud intact and lined up with the fan? Is the shroud missing?Is your radiator clean inside and out? Check for heavy calcium deposits in the radiator. Is the water pump ok? Two things make it overheat while stopped. Not moving enough air through the radiator or not moving enough water through the system.
Carburetor for Dodge 440..Carter turbo Quad James Murphy 9-17-02  
I need to find info on this carb. Any info that you can help me with, it sure would help. I am looking to replace the one I have now.

Thanks in advance. Jim
Re: 78 Dodge 440 overheating Bill 5-19-04  
I am currently in the midst of solving an overheating 76' Southwind Class A with the 440... if you want to find out if it is the airflow that is causing the problem, remove the engine hatch (class A's), drive it, and see if it still heats up as much. There are only two main reasons for overheating, either not enough airflow or not enough water flow... at this point I am fairly certain that mine has poor airflow. I have installed a new radiator core, and a clutch fan for a 1972 Chevrolet 1-ton duelly with standard transmission and a/c, the "severe duty" model. This combined with my original equipment existing 7 blade generated so much airflow that the fan actually cavitated because it is unable to exhaust the air efficiently past the engine, which fills virtually the entire space provided for it. I plan to install sheet metal ducting to create the kind of airflow that the RV manufacturer failed to address in the original design of the engine hatch. To be fair, this may not be the easiest solution to grasp and complete from scratch... some knowledge of airflow charactaristics is necessary. My design includes a duct below the fan which drafts air out below the engine; a second duct at the rear which does the same thing; enlarging the engine hatch by increasing the height by 6"; Adding a hood scoop forward of the radiator to insure adequate air supply. Of course, ensuring that all the other points made by others regarding the overheating 440 are valid and should be addressed. Where you begin depends upon where you are... naturally. A tight, clean system in good condition with the correct parts installed is always the best first step, and need not be expensive. Flow test the radiator and inspect it for useable condition. Check the water pump for correct part #. The motorhome model has 12 blades on it. The automotive part for the same engine has only 6. Check the thermostat. The RV model is two stage... most parts houses don't even know what it is. The original RV model must be installed. Flush the engine well, especially if it has been sitting for a long period of time. Check the fan clutch. If it has a slight wobble, actually any wobble at all, it is suspect. Also look for any oil seeping out near the base of the shaft. Replace it if necessary. Obviously, the hoses and fan belts need to be in good condition and properly clamped and adjusted. Check the engine timing. If the timing is advanced too far, the engine will build up heat too quickly to dissipate. Again, where you start depends upon where you are. Most of us have purchased our old RV's used. You just never know what someone has done to it before you own it. Ya gotta check things carefully and thoroughly, and don't assume anything.
Re: 78 Dodge 440 Carb Dili 5-18-07  
Help! I am in the process of restoring a 1978 Winnebago Brave on Dodge platform. Being a GM fan, I know very little about Mopar. Before investing money I wanted to ensure the engine ran (supposedly a 440) The existing Holley leaked to the point of filling the intake manifold galley with a puddle of gas. Not knowing what kind of replacement, I just grabbed a 72 Rochester Quadrajet, added a few gaskets and longer bolts to get the 1-1/2" secondaries to open in the stock 1-3/8" secondary bores. I rigged up a hotwire to the electric choke and an aftermarket electric fuel pump pulling fresh gas from a gas can. A shot of starting fluid, a couple of stumbles and she ran like an escaped convict! What carb do you suggest for this motorhome if it is a 440 or a 400? Is there any tweaking I could do to fine tune this Quadrajet as I must return it to my 72 Electra 225? Any help or suggestions are appreciated, Thanks!
Re: 78 Dodge 440 overheating Troy 8-2-02  
The flex fan was on the motorhome when I bought it, and I put in the 180 thermostat. Yes it has a shroud and the fan is inside it. I was wondering if I should get a fan clutch and fan to replace the flex fan? Thank you for your help.
Re: 78 Dodge 440 overheating ralph 8-2-02  
I have been down this road. My guess is that the flex fan was installed because of the overheating problem. A clutch fan will not improve the situation. If the MH has the origonal radiator it is probably clogged and I would suggest a rebuild. My 78 440 MH heating problem was solved with a rebuilt radiator and works fine with the origonal clutch fan.
Re: 78 Dodge 440 overheating nick 6-24-04  
Check your thermostat to make sure it is a reversed poppet type. if it is just the plain disk type it will cause the overheating. You can find the correct one through Milodon
Re: 78 Dodge 440 overheating Sam Watson 8-2-02  
A word of advice on flex fans and RVs. By design, a flex fan is meant to change the pitch of it's blades, thereby moving less air at higher RPMs when the forward motion of the vehicle---25MPH +---will "ram" air through the radiator. All well and good, but how about those mountains where you're down in 2nd, maybe even low, and turning 3,500 RPM while grinding along at 20-25 MPH, that's when you need max airflow, and you can't get it with a flex fan. Bear in mind also, that some coach designs just don't have good airflow through the radiator/engine compartment. The truck chassis was designed to have an angled "toe board" at the rear of the engine bay. This angle is part of the airflow design,the slight vacuum it creates helps to move air out at the rear of the engine bay, preventing blocking of airflow and creation of a higher pressure area in the engine bay, resulting in reduced airflow through the radiator.
Re: 78 Dodge 440 overheating Ray 8-4-02  
I have a 77 apollo with a M500, 440 dodge. Had heating problems while at idle. I bought a fan clutch from the Mopar section of either the Jeg's or Summit catalogs and it cured my problem.
It is the fan clutch and fan for the big block 440 muscle cars of the 70's.
If you go to the dealer they will look at you like your crazy. the days of the old knowledgeable parts guys are gone. you can go to the Summit or Jegs web site to order. direct bolt on.
Re: 78 Dodge 440 overheating Roger 8-10-02  
Also had this problem.......
check out that someone didn't install a Mopar "AUTO" water pump........the blades on that are 1/3 that of the RV version.....the clutch fan also was a culprit..Sam knows what he is talking about!
Re: 78 Dodge 440 overheating Bob 8-27-02  
Run, don't walk to a radiator shop. Have them thoroughly clean your radiator. Replace if necessary. If you still have overheating problems, you know you have a solid foundation to build upon. Here in the south two to three years is about all you can get before a good cleaning is necessary.
Re: 78 Dodge 440 overheating Marti 9-24-02  
My son and I have had several 440's in street/bracket race cars. If we used a good, clean three row radiator we never had a heating problem, even when running race after race. We used the flex fan you describe. We always ran 160 degree thermostats. You probably have the problem solved by now, but I can tell you that it is not a problem when everything is in good shape.
Re: Carburetor for Dodge 440..Carter turbo Quad Marti 9-24-02  
What do you need to know about your Thermoquad? We have run them in single and dual applicatins, and found them to be a very good unit, easily tuned, with many provisions for tuning. They run a whole lot better than a Quadrajet or an AFB!
Re: 78 Dodge 440 overheating Jim 6-22-03  
I have a 1977 class A with a 440 dodge. We have driven across the country. Towed a small truck thru the Rockies. And regularly battle a head wind going uphill. Here are the things I've done to get maximum performance while keeping things cool:
1. new plugs and air filter every year
2. new high temp ignition wires
3. duct cool air into the air filter
4. new dual exhaust
5. new rad cap and new rad fluid
6. factory spec thermostat
7. completely remove all air from rad system by adding $5 rad flush connections to all high points in the heater hoses and use them as high point vents and fill points

I'm thinking about installing a flex fan. I just removed the old fan clutch to make sure it's ok.
Re: Carburetor for Dodge 440..rv Ken 5-23-12  
I have a 78 dodge rv with a 440 what kind of carburetor is good for this
Re: Carburetor for Dodge 440..Carter turbo Quad Ron 10-27-02  
I've had nothing but trouble with my '78 Thermoquad twice rebuilt, and after 3 years of battling, I trashed it. I put on a '78 Cadillac 425" quadrajet I got at a junkyard for $15 and have never had a problem since. Lose that Thermoquad is my advice!!
Required fields in red
For more info about a field, place your mouse over the More Info icon.
Your Name:
Your Email:

Code is case-sensitive. Helps stop SPAM.

Advertise Here
Get Media Kit NOW!

Get Media Kit to Advertise!

Advertiser Links

Back to Top