454 getting too hot

[seilerbird]

No, I don't have an electric fan installed. I didn't even know that could be done.

 

[34footer]

You drove that MH all over during the summer, what temp was it running then?
J

 

[Luca1369]

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.....

I have one myself, also wired to a switch on the dash.  I don't run it all the time but if I'm going up a mountain, it will be on, and it does help.  Good on hot days in rush hour traffic too.

 

[seilerbird]

You drove that MH all over during the summer, what temp was it running then?
J

I have no clue. The temperature gauge and the oil pressure gauge have never worked since I owned this thing. Both have been pegged at max either off or on. This thing has a lot of small electrical problems like that. Even if they did work I could never see them from the drivers seat without standing up since they are so poorly located. I just got a set of gauges at the auto parts store and had a mechanic install them. So this is the first time I had a clue as to what temperature it was running at.

 

[34footer]

Are the new gauges a top quality, like Stewart Warner, Autometer, Sun? If not, and you are not boiling over, the gauge could just be reading high.
J

 

[DonTom]

I have no clue. The temperature gauge and the oil pressure gauge have never worked since I owned this thing. Both have been pegged at max either off or on. This thing has a lot of small electrical problems like that. Even if they did work I could never see them from the drivers seat without standing up since they are so poorly located. I just got a set of gauges at the auto parts store and had a mechanic install them. So this is the first time I had a clue as to what temperature it was running at.

It's usually an easy fix in a GM. If it's always pegged, you should be able to un-peg it by moving the needle past the stopper that's leaving it pegged. You just have to take things apart to get into the dash. IIRC, sometimes you might have to bring back the needle more than 360 degrees for it to work correctly. But if you can get your finger on the needle, you should be able to fix it yourself.

I had that problem in two old GM vans and fixed them both myself. However, the reason they might be pegged to begin with could be from a bad connection on the sensors. With no connection, they peg. If they peg past the needle stopper, they will stay pegged even when everything is off.

But more than likely, somebody once worked on that thing with the sensors disconnected and then turned on the ignition and didn't know what to do from there when the needles pegged or didn't want to take the time to fix the pegged needles.

-Don- SF, CA
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[Jeff]

Tom:

We had an 83 Pace Arrow on a P-30 chassis that had both of the symptoms you describe:

First the gauges, the P-30 instrument cluster has a ground behind the dash that corrodes and as the contact is lost our gauges all started reading high except (IIRC) the fuel gauge that got erratic. Creating a new ground to the engine block fixed that problem.

Then the radiator temps. After about 10 years and 60-70,000 miles the temps started rising above what had been normal on summer days in hill country and in city traffic. We tried everything including changing the bi-metal fan clutch to no avail. As someone mentioned I believe the radiator was getting plugged but I alleviated the problem with an electric fan system with two small 12V motors and fans mounted in a plastic case that sat in front of the radiators and was controlled with a panel switch and a fixed thermostat on the fans. I used the switch to override the thermostat because it had the fans running all the time. As the mileage got up to 100k I had to use the fans more and more in warm weather but never had a boil over.

 

[seilerbird]

Are the new gauges a top quality, like Stewart Warner, Autometer, Sun? If not, and you are not boiling over, the gauge could just be reading high.
J

I don't think it is a problem with the gauges reading high. It reads 190 as I am cruising at 50 mph or so. The problem only pops up when I sit at a traffic light for two minutes and the temperature rises 20 to 30 degrees. I have never had a vehicle do that before so I am guessing something must be wrong. Adding fans might be a good temporary fix but I feel like I really need to get the radiator removed and rodded out.

 

[seilerbird]

It's usually an easy fix in a GM. If it's always pegged, you should be able to un-peg it by moving the needle past the stopper that's leaving it pegged. You just have to take things apart to get into the dash. IIRC, sometimes you might have to bring back the needle more than 360 degrees for it to work correctly. But if you can get your finger on the needle, you should be able to fix it yourself.

I had that problem in two old GM vans and fixed them both myself. However, the reason they might be pegged to begin with could be from a bad connection on the sensors. With no connection, they peg. If they peg past the needle stopper, they will stay pegged even when everything is off.

But more than likely, somebody once worked on that thing with the sensors disconnected and then turned on the ignition and didn't know what to do from there when the needles pegged or didn't want to take the time to fix the pegged needles.

-Don- SF, CA
​

The factory gauges are worthless. Even if they worked perfectly they are useless if I can't see them when I am driving down the road. It is a poorly designed cockpit. There used to be an overhead bunk above the drivers seat. I felt like I was sitting in a bucket when I drove the motorhome. I couldn't even see the speedometer, much less the gauges. I removed the bunk and raised the seat up 4 inches. Now I can see the road and the speedometer but the only way I can see the gauges is to stand up, which is not a good idea to stand up every minute when I am driving. Fixing the old gauges never crossed my mind. I had to install 3rd party gauges in a place where I can see them when I am operating the vehicle.

 

[wackymac]

In the 1970s I used to peg the speedometer of my 1958 VW bus but it never stuck.  When I let up on the gas pedal the speedometer would come off the peg and unwind.  It wasn't electrical, it was mechanical, driven off the left front wheel.

 

[DonTom]

The factory gauges are worthless. Even if they worked perfectly they are useless if I can't see them when I am driving down the road. It is a poorly designed cockpit.

Oh, perhaps they were disconnected from their sensors. Perhaps the sensors were used to run the non-stock  gauges and that would explain why the stock gauges are now stuck  pegged.

-Don- SF, CA

 

[seilerbird]

Oh, perhaps they were disconnected from their sensors. Perhaps the sensors were used to run the non-stock  gauges and that would explain why the stock gauges are now stuck  pegged.

-Don- SF, CA

Nope, the sensors were hooked up properly. There is several problems with my instrument cluster. The temp and oil gauges are pegged at all times, either with the ignition on or off, or with the sensors hooked up or not. When I turn on my headlights the right blinker indicator glows. The right blinker works fine. The high beam light glows, and the high beams and low beams work fine. Sounds to me like someone has crossed a wire somewhere.

 

[Ernie n Tara]

All of your instrument problems sound like a bad (loose or corroded) ground. Weird things happen when the electrons get loose.
Ernie

 

[PancakeBill]

I am with Ernie, or is it Tara?  If your dash cluster hinges up, check all the connections you can find, grounds, plugs, pull out, spray with cntact cleaner and replug.  Often there is one big connector.  Your coach is older, been on the road, been stored, after this many years, things can loosen, corrode etc. 

Of course, this addresses the existing gauges, not the overheating.  I stick by my flush the cooling system on that one.  Way way back, our first RV trip across the country (1972) my 1965 van (pulling a tent trailer) overheated often, most of that was due to clogged cooling passages, plus bad airflow. 

 

[adun015]

"I can't check for cold spots once I warm up since there are two other radiators blocking access to the radiator."

Sure you can, I have the same set up with two Aux rads. One for the tranny one for the oil.

 

[ranger magnum]

Ive been dealing with what I believe to be higher than normal engine temps. In the desert during the summer, with outside air temps at or above 100, my 87 454 powered bounder is seeing temps hit 250 while pulling grades.

Ive flushed the radiator and added 2 1300 cfm fans. I also added an oil cooler, and in the next day or two, im going to add another radiator in line with the heater core that will take the place of the heater core bypass. The fan clutch is new.

I have a full array of gauges, including trans temp. Earlier in this topic a guy mentioned seeing temps hit highs just south of 300. I have yet to run the rv with the added fans/cooler, but plan on it soon.

 

[2harley1vectraguy]

hi everyone new guy here , my 95 34ft winni vectra runs about 200/210/ tow a ten ft trailer to bikes,so about 4/6 000 lbs,rv is 16/17000.lbs..if i fell its runnin hot i pop it outta gear when im over a big hill,, down the other side and it cools down, it makes me nervus if i see it above 210 tho ,so i just drive at night ,she will run 190 all night,and i can relax, check the air idel control valve as well,if open will suck air and power loss, will make things get warm to.i even run the back heater if i feel its gettin to hot on a hill,leav back vent open heat gos out vent ,prob.solved,,,good coolent  is key,go to auto zone pick up some liquid ice ask thay sell it , will drop temp 10/15 deg,,,,,,works with all antifrezz try that,,,,good luck and keep cool ......

 

[SeilerBird]

Ive been dealing with what I believe to be higher than normal engine temps. In the desert during the summer, with outside air temps at or above 100, my 87 454 powered bounder is seeing temps hit 250 while pulling grades.

Ranger -That was an old post of mine under a different id.

This has not been a good week for Bounders.

The temperature my 85 Allegro operated at went up and down with the outside temperature. It went up when I was idling and down when driving. I flushed the radiator, replaced the thermostat, replaced all the belts and hoses, and replaced the cap. Nothing changed it.

Now I have traded the Allegro in on a 94 Damon with a 454 and it is as different as night and day. The temp stays rock solid at 200 once it warms up. So I am at a loss to explain it.

 

[ranger magnum]

So I had a long conversation with the owner of the last mom and pop auto parts store in town. He is an rv'er as well, and is very knowledgable. His opinion is that some engines and some rv configurations just run hot. The engine can handle that heat, but the cooling system is near the edge.

While my rig hasnt overheated, I dont like the fact that it runs about 30 degrees higher than i like. On the flats, its a steady 215-220. On grades she has hit 250. The oil cooler added about a quart of oil, and i got a 2 quart oil filter. I plan on making an auxiliary radiator out of 1/2" copper pipe, amd that will add about a half gallon of water. It too will have its own fan.

I should have it done in a week or two

 

[waldo]

Just to toss in my 2 cents worth...

Many years ago, I owned a 1989 3/4 ton Suburban, powered by a 454.  I used it to tow a 5,000lbs boat to the Colorado River from the Los Angeles area. 

It performed well for several trips, then decided to start running "hot", the temps went up to 220... and, the towing performance dropped off dramatically.  Around town and not towing, all seemed well.

I had it checked out by a Chevrolet dealer and they found the head gasket, between the two center cylinders, had burned, allowing combustion gasses into the coolant.  The shop pulled the motor down and found the pistons in  those cylinders had also been burned slightly.

Chevrolet ended up replacing the engine under warranty.  Within two months, I came back with the same issue.. they replaced the engine again.

As it was explained to me, in the early 454s, as with all of the big blocks at the time, there was no water jacket between those cylinders.  And because the cylinder walls were so thin on the 454s, they couldn't handle the heat generated under extreme conditions.

To remedy the situation, GM redesigned the 454s slightly, adding a water jacket between the problem cylinders and that, apparently, solved the problem. 

When Chevrolet replace my engine for the third time, I paid the difference and had a "Tonawanda" 454 put in and had no further issues with motors goin' south.

At the risk of wearing out my welcome, there's another thing folks can do to help cut down on heating problems... I did this and it seemed to work.  Wrap the exhaust manifolds with "header wrap", it's designed to keep exhaust heat from radiating from thin wall headers and heat soaking other underhood components.

The engine bays in motor homes tend to get pretty closed in and airflow through the compartment is compromised.  This high ambient heat does nothing to help an engine that already tends to run warm. 

In my Suburban, I also installed two boat bilge blowers, one on each side of the compartment, set up to pull hot engine compartment air and exhaust it out, under the truck.  I don't know how much they did, but every little bit helped.