454 getting too hot

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seilerbird said:
The problem is that no manual came with the motorhome. Tiffin has not been very helpful with customer service in the past, but I will email them and see if I can get the info.
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If all esle fails, there are places on the web that sell used automotive manuals. Perhaps you can find one for yours, if you get lucky.

I always get the shop and owner's manuals for every vehicle I own.

-Don- Reno, NV
​
 
If you have a ford dealership they can flush the radiator of smaller vehicles, I'm sure they can flush the motorhome radiator for you. It's going to cost but it will remove all the grime from the radiator and heater core!
 
One other thing you may want to check is the engine timing. It may seem to be running okay but 3-4 degrees off in timing can affect engine temperature. At least it's something you can eliminate by checking.
 
seilerbird said:
I got a set of gauges installed on my motorhome and I have an engine temperature problem with my 85 Allegro 454. The temperature runs about 210. First thing I replaced was the radiator cap and that didn't help. There is no fluid leaks and the fluid is at the proper level. I believe my engine has a clutch fan and I never hear it run even when it climbs to 220. So I am guessing that I will need to replace the thermostat and the clutch fan. Any one have any other ideas?    IS KARMA CATCHIN UP WITH ME?
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seilerbird said:
There are two coolers in front of the radiator and they look relatively dirty. Can I just go to a 25 cent car wash and hose away the dirt? Or should I just use a garden hose hooked up to city water with a nozzle?
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I was told by my cousins, who have been truckers/mechanic types all their lives, to use air to blow out the radiator fins first then water.    If you use water the dirt can change to mud and stick on.  Also seeds in the dirt can swell and get really stuck on.

This was in the context of my cousin driving a tractor trailer through Death Valley in early July of this year.  It was somewhat overheating in the day so he only drove it at night for that streatch.
 
Another thing to check on the radiator are the fins of the radiator, oil cooler and AC. If too many are flattend then the air flow will be restricted. I had a Bronco II that would heatup while driving in town. I was going to pull the radiator to have it flushed, and discoverd that alot of the fins were puched over. I took a small flat blade screw driver and a pair of needle nose pliers and strighted them all out (I didn't know about fin combs then). After strightening them out I saw a lot of dead bugs, dirt and grass in the air space. I pulled out my pressure sparyer and sprayed the radiator out from the inside out. You would not believe the dirt and junk that came out of of it. About an hour to do the work and it took care of my tempiture problem.

I suggested this to a MH owner who was having problems, and he responed back that it was the best $2.25 he ever spent (he went to a car wash.)
 
Tony_Alberta said:
I was told by my cousins, who have been truckers/mechanic types all their lives, to use air to blow out the radiator fins first then water.    If you use water the dirt can change to mud and stick on.  Also seeds in the dirt can swell and get really stuck on.

This was in the context of my cousin driving a tractor trailer through Death Valley in early July of this year.  It was somewhat overheating in the day so he only drove it at night for that streatch.
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I don't have access to compressed air so this morning I went to a 25 cent car wash and cleaned the radiators as best as I could. I haven't driven much since then so I don't know the results yet.
 
One thing about using high pressure water is the possibility of flattening fins.  All tings considered, I think a radiator flush is a priority. then new coolant.  The flush should also help clean any inside coolant passages.  When it starts heating, have you tried turning on the dash heat?  If it drops, it may also show diminshed cooling.
 
PancakeBill said:
One thing about using high pressure water is the possibility of flattening fins.  All tings considered, I think a radiator flush is a priority. then new coolant.  The flush should also help clean any inside coolant passages.  When it starts heating, have you tried turning on the dash heat?  If it drops, it may also show diminshed cooling.
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I was very careful with the high pressure hose, but it wasn't really high pressure at all, kind of a medium pressure. I agree the radiator flush and new coolant is a priority. I am also going to replace the thermostat, since it doesn't seem to be acting properly. I will to all this next weekend after my next paycheck. I will also get the engine timing checked then.
 
I have a 1987 454 motor home that runs on the hot side 220 or better all the time i have even seen my gauge hit 300 when pulling cajon pass with a six thousand pound trailer motor home is a 37 footer and she is heavy what you have o realise is that the sending unit sits between two cylinders so that small amount of water is going to be hotter than anywhere else in your motor. point being if your engine is not spewing or boiling fluid i would look at installing a trans temp guage this will give you a better ave. on your temp as your fluid runs through radiator so both fliuds will be around ten degrees of each other. my 454 has never boiled or left me stranded although with the loads i tow and carry she is a very thirsty girl.........hope this puts you at ease. 8)
 
I took it out for a longer drive today and I feel much better now. The gauge stayed at 190 until I stopped at a light, then went to 200. It is acting like the thermostat is ok, but it looks like it needs a coolant flush.
 
What you are describing is exactly what I ran into with my 85 454 4bbl. I did have a bad fan clutch which was repaired and I got a radiator flush but it did not stop the overheating. What I found was that the radiator was stopped up. Check for cold spots when you have warmed up. This is a sure sign of a clogged radiator.  There is a place in Burlington N.C. that I got mine boiled and rodded out and that was the cure. No problems since. Guy did a great job and turn around was super fast. I will have to look back on my receipt but if interested let me know & I will get the business name & number.
 
adun015 said:
What you are describing is exactly what I ran into with my 85 454 4bbl. I did have a bad fan clutch which was repaired and I got a radiator flush but it did not stop the overheating. What I found was that the radiator was stopped up. Check for cold spots when you have warmed up. This is a sure sign of a clogged radiator.  There is a place in Burlington N.C. that I got mine boiled and rodded out and that was the cure. No problems since. Guy did a great job and turn around was super fast. I will have to look back on my receipt but if interested let me know & I will get the business name & number.
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Thanks for the info. The clutch fan works fine and I have flushed the radiator. The temp stays on 190 until I sit at a signal light, then it can go up to 210. It returns to 190 after a mile or two. I can't check for cold spots once I warm up since there are two other radiators blocking access to the radiator. I am positive I need to have it flushed out and that will be expensive, so it will have to wait until next month. Meanwhile it is drivable if I keep my eye on the temp gauge. I am headed to Arizona and I will have it done once I get there.
 
Sounds to me like you don't have an overheating problem at all. It's normal for the temp to rise a few degrees while stopped and idling. 190-220 range is normal. Unless the temp climbs up into the hot range don't get paranoid. You can do a radiator flush but I doubt you'll see much of a change in the temperature. Checking the cleanliness of the radiator fluid and for sediment in the bottom of the fill tank can give an indication of the condition of the radiator. I'd drive it more and get more of a feel if there really is an overtemp problem.
 
30yrnavy said:
Sounds to me like you don't have an overheating problem at all. It's normal for the temp to rise a few degrees while stopped and idling. 190-220 range is normal. Unless the temp climbs up into the hot range don't get paranoid.
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Agreed that the current behavior isn't likely a problem.  I was driving my aunt's minivan which overheated while we were stuck in traffic.  As she only ever drove in 10 or 15 minute chunks around town or on a freeway with never a blockage the minivan fan could've been faulty for a year or more. 

I've also noticed that my vehicle temp gets close to overheating in 85-90 F weather going up hills.  But that's also with the A/C going.  I suspect that if I was to turn off the A/C while going up the hills there wouldn't be a problem.  And it cools down to normal range within 5 or 10 minutes.

 
 
30yrnavy said:
Sounds to me like you don't have an overheating problem at all. It's normal for the temp to rise a few degrees while stopped and idling. 190-220 range is normal. Unless the temp climbs up into the hot range don't get paranoid. You can do a radiator flush but I doubt you'll see much of a change in the temperature. Checking the cleanliness of the radiator fluid and for sediment in the bottom of the fill tank can give an indication of the condition of the radiator. I'd drive it more and get more of a feel if there really is an overtemp problem.
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Well right now I am at sea level with no mountains (Florida) and it is 60 degrees outside. I am wondering how it will act going up mountain roads in the west in 90 degree heat.
 
Water boils at 212F but it is much higher when under pressure.  I don't remember the number right now.
 
With an 11 lb. Pressure cap, plain water boils at about 240 degrees.  Raise that to about 260 degrees if you're running a 50/50 ethelyne glycol and water mix.
 
I just replaced my cap and it is a 16 pounder and I am running 50/50.
 
do you have an electric fan installed???........i've seem a few of these rigs [including my old bounder] with one in the front end...........i haven't used mine yet..... but they say they help alot especially in traffic.........and setting still........i have mine wired direct to a switch on the dash.....
 
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