Foretravel Owners' Forum

Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: johng on September 23, 2015, 12:07:17 am

Title: rear 460 ford rebuilt still overheating
Post by: johng on September 23, 2015, 12:07:17 am
Ford 460 rebuilt.  trans rebuilt.  Rad recored.  Still runs hot.  oversize fan installed.  Can someone advise if this setup is supposed to blow out through rad or pull in.  There is a shroud around the rad on the inside so we wonder how air flow through rad works thanks
Title: rear 460 ford overheating
Post by: johng on September 23, 2015, 12:18:46 am
any ideas  we have rebuilt motor  rebuilt trans  recored rad ' on 19909 grand gas pusher.  can someone advise if this setup blows air out or pulls air in through rad
Title: Re: rear 460 ford overheating
Post by: johng on September 23, 2015, 12:24:40 am
overheating
Title: Re: rear 460 ford rebuilt still overheating
Post by: Pierce & Gaylie Stewart on September 23, 2015, 01:00:48 am
Does it run hot all the time? In town, highway, etc. No trapped air in system? Thermostat new? 50/50 coolant mix?

If problem persists, have radiator shop check for products of combustion in the coolant. Checking torque on the heads might also be in the cards. 

Pierce
Title: Re: rear 460 ford rebuilt still overheating
Post by: TAS69 on September 23, 2015, 07:30:55 am
I'm 90%positive rear radiators exit the rear. Blow out huge pull from drafting out going down the road.. Wonder if your machine shop checked your heads for cracks? Would have been great opportunity to zero deck the block while it was torn down. Slim chance a timing issue could get temps to climb.
Title: Re: rear 460 ford rebuilt still overheating
Post by: John S on September 23, 2015, 07:40:06 am
This is an issue with gas pushers most of the time.  How much it overheats is the question. 
Title: Re: rear 460 ford rebuilt still overheating
Post by: bbeane on September 23, 2015, 08:07:28 am
No personal experience with rear engine gas, but as I understand it running hot was an issue. If no mechanical issues, you may consider a electric aux fan. You may also have your radiator shop build you a thicker (more rows) radiator.
Title: Re: rear 460 ford rebuilt still overheating
Post by: nitehawk on September 23, 2015, 08:27:32 am
When I was into stock car racing a friend tried many different fans (number of blades) and shrouds. He asked me to take a look at his setup. I took one look, told him it would cost him a sixpack of Pabst to find out what was wrong. After we drank three shorties each I told him to take out the spacer behind the fan because it put the fan too close to the radiator. Never overheated again.

Our coach has one engine mounted fan and two electric fans on the rear side of the radiator and a shroud on the engine side.. Almost never reaches 180 degrees.
Fans do push (or pull) the air out the back of the coach. One heck of an air flow coming thru the rear grill door.
Title: Re: rear 460 ford overheating
Post by: nitehawk on September 23, 2015, 08:39:34 am
Logic would seem to dictate that: seeing as how a vacuum is created at the back of the coach as it is going down the road the fan should push the air rearward/outward, into the vacuum area. Is it possible you have the fan reversed?
Title: Re: rear 460 ford overheating
Post by: TAS69 on September 23, 2015, 09:02:15 am
Blows out. Wonder if it has a cracked head?
Title: Re: rear 460 ford overheating
Post by: Tim Fiedler on September 23, 2015, 09:03:42 am
Plus even though it may be new, confirm thermostat operation Cooling was always marginal in my 36' 460 OREG
Title: Re: rear 460 ford rebuilt still overheating
Post by: Twig on September 23, 2015, 10:34:27 am
Doesn't matter which way the air flows at this point. If you suspect that may be the problem, reverse the fan and see if it helps, if not it's a different problem.
Title: Re: rear 460 ford rebuilt still overheating
Post by: Dub on September 23, 2015, 10:38:37 am
TAS69... when he says "blow out thru the radiator" I think he means air thru the radiator and not coolant blowing out the radiator...I know it's frustrating after a rebuild on the engine and radiator.. I would sure follow up as Tim mentioned and replace the thermostat and then check into the fan distance from the radiator as nitehawk mentioned... I can't add anything now but I am studying it.
Title: Re: rear 460 ford rebuilt still overheating
Post by: Tim Fiedler on September 23, 2015, 10:53:03 am
My 460 was CHRONICLY hot. Blew it up (actually head gaskets) on trip back from NY to Chicago towing my element on a 80 degree day. Bigger radiator would help, maybe a "water mister" system and aux electric fan. Still would have awful gas mileage. Decided not to rebuild and traded at MOT for my 1999 U-270. If I was doing it over, i sure would have looked around for a Diesel swap, but cooling would have to be addressed with that solution as well.

Not sure how the ORED's were cooled, but the OREG's were underpowered and tended to overheat. And mileage on a good day might reach 6 MPG....

Loved the coach, hated the power train....
Title: Re: rear 460 ford rebuilt still overheating
Post by: bbeane on September 23, 2015, 12:02:03 pm
A long while back ( early 80s) we had a number of 460s, as Tim says they all seemed to run hot. Some we put larger radiators in, as well a high performance fan blade with more blades. We did ware fan belts with the bigger fans though.
Title: Re: rear 460 ford rebuilt still overheating
Post by: nitehawk on September 23, 2015, 12:18:59 pm
Just had a thought (hope I didn't hurt anything!)

Did you check the upper & lower hoses for blockage? I recall, years ago, where the wire inside a lower hose broke apart and obstructed the flow.
Title: Re: rear 460 ford rebuilt still overheating
Post by: P. Wyatt Sabourin on September 23, 2015, 01:08:11 pm
I recall reading a thread on Foreforums describing how someone reversed the airflow with the 460 gas from "in the rear" to "out the rear" which fixed the overheating problems. This article noted that power washing or steam cleaning the radiator annually was required because dirt/oil from engine accumulated on the radiator with the airflow going out the rear. You may be able to find this thread on this site.
Title: Re: rear 460 ford rebuilt still overheating
Post by: Keith and Joyce on September 23, 2015, 03:12:14 pm
I second the hose problem.  Had a bottom hose on a dump truck where the inner part came away and would block flow.  Took a while to find that one.

Keith
Title: Re: rear 460 ford rebuilt still overheating
Post by: Raymond Jordan on September 23, 2015, 03:50:59 pm
As Wyatt was saying, someone who had reversed the flow, to out the rear, had fixed their cooling problem. There were postings on the old forum talking about this. Best of luck.
Raymond

Title: Re: rear 460 ford rebuilt still overheating
Post by: Michelle on September 23, 2015, 04:03:19 pm
As Wyatt was saying, someone who had reversed the flow, to out the rear, had fixed their cooling problem. There were postings on the old forum talking about this.



Overheating (http://www.foreforums.com/index.php?topic=4579.msg18383#msg18383)

Gas pusher overheating update (http://www.foreforums.com/index.php?topic=1971.msg6493#msg6493)
Title: Re: rear 460 ford rebuilt still overheating
Post by: red tractor on September 23, 2015, 08:32:11 pm
The original fan pulled air through the radiator, which always looked like it should have been the other way to blow the air out from the engine through the radiator. The fan belts have to be very tight to keep from slipping which slows down the water pump. Also on the earlier coaches had to install different pulleys to slow down the fan blades as it was going to fast causing it  to cavitate like has been said, they tend to run hot, were a 55 mph vehicle
Title: Re: rear 460 ford rebuilt still overheating
Post by: TAS69 on September 24, 2015, 02:39:08 pm
TAS69... when he says "blow out thru the radiator" I think he means air thru the radiator and not coolant blowing out the radiator...I know it's frustrating after a rebuild on the engine and radiator.. I would sure follow up as Tim mentioned and replace the thermostat and then check into the fan distance from the radiator as nitehawk mentioned... I can't add anything now but I am studying it.
I understand he doesn't want coolant blowing out of anything😜 A cracked head that was missed by machine shop could cause overheating! Rear radiator vehicles such as 225's exit "out" the rear lest the fan have to fight the considerable vacuum created at anything beyond parking lot speeds.
Title: Re: rear 460 ford rebuilt still overheating
Post by: red tractor on September 24, 2015, 09:21:04 pm
We had one of the fuel injected coaches that had a clogged catalytic converter, which caused it to overheat
Title: Re: rear 460 ford rebuilt still overheating
Post by: nitehawk on September 25, 2015, 08:05:55 am
Just had another thought!! Gotta be careful, as I might be overheating my tiny brain!!

I wonder if the lower radiator hose is collapsing when the engine is turning over at higher RPM? I would have someone watching the hose(s) while the engine is slowly increased to highway RPMs.
Some water pumps can draw so much fluid that the thermostat won't let enough fluid thru and then the lower hose collapses. That is the reason for an inner support--to keep the lower hose open.
Title: Re: rear 460 ford rebuilt still overheating
Post by: turbojack on September 25, 2015, 10:46:40 am
As I was reading this, I somewhat remember a friend of mine use to own one of these when then were new and had all kinds of problems with it overheating.  I think the solution was Foretravel put a scoop on the side of it to get cool air into the engine area instead of the radiator getting it's air from under the coach.

The problem with rear radiators in the south during summer the pavement temperatures are 130-150 degrees. With the radiator blowing out it is getting the air going into the radiator from under the coach so it is getting hot air (?120+) due to the pavement and also having to pass the hot engine.