Community Forums

Pexring · 07-15-2014, 12:42 AM

Those of you running Class A on a Chevy chassis with a 454 motor. What is your average engine temp? Mine likes to run around 220-240 degrees F, which is just off the red line which keeps me nervous. Recently had a mechanic go through the motor. Replaced a hose which was about collapsed and the thermostat. Didn't make a whole lot of difference. Some one told me 454's tend to run warm. Do they???

sknight · 07-15-2014, 01:34 AM

I'd have the radiator checked, the tubes could be getting stopped up and if the fan clutch is stock then it's due for replacing.

220* is high as I'd like to see max.

Tomtall · 07-15-2014, 01:40 AM

Our prior RV had a 454 and my gauge never would go much above 200 F deg.. I ran a 180 deg. thermostat , fatotory vicous fan with two electric fans as back up. Only used the electric fans in stop and go traffic. Are you positive your gauge and sending unit are giving you a correct reading? If so it sounds like your running a little warm for comfort. Have you done a radiator flush? Also make sure all your factory rubber flaps are in place around your radiator to help direct airflow thru the radiator. Our Superchief had several of them. I also found that my 15 PSI radiator cap was bad when we first bought our RV. If not kept under pressure your boil over point becomes lower. Just a few things to consider.

Good luck !

C350AMG · 07-15-2014, 02:30 AM

In my 454 vortec the gauge I found not very accurate. I have an obd2 connector with dash command (on iphone ). Temperature usually is very stable at 205-210, on huge mountain passes went up to 225

George Schweikle · 07-15-2014, 08:46 AM

Your temperature gauge is probably bad. Plus it's not very accurate to begin with...

If you have the original GM dashboard like me, I have found the temperature gauge reads lower than either my current scangauge, or an aftermarket temperature gauge on the previous motorhome. The bottom line is that the GM gauge is not very accurate. Either get an aftermarket gauge and sending unit, or a scangauge that reads everything the engine CPU sees.

When the dashboard gauge failed on my previous Diesel Trek, it jumped between 0 degrees and 260.

On my 1999 GM 454 gas (80,000 miles) the scangauge reads 193-198 degrees on level ground towing a car trailer weighing 5000lb. Mild grades raise the temp. to 203-205. Yesterday, 95 degrees ambient temperature and a long steep grade on a secondary road = 215.

Quote:

Originally Posted by Pexring

Those of you running Class A on a Chevy chassis with a 454 motor. What is your average engine temp? Mine likes to run around 220-240 degrees F, which is just off the red line which keeps me nervous. Recently had a mechanic go through the motor. Replaced a hose which was about collapsed and the thermostat. Didn't make a whole lot of difference. Some one told me 454's tend to run warm. Do they???

Tom N · 07-16-2014, 09:56 AM

Your temperature should not deviate much from the temperature of your thermostat.

If you have a 195 I would be concerned if the temp went over 210 climbing a hill in hot weather.

If it does I check for a dirty radiator, glazed fan belt and then the thermostat itself.

-Tom

chboone · 07-16-2014, 10:54 AM

Quote:

Originally Posted by Pexring

Those of you running Class A on a Chevy chassis with a 454 motor. Replaced a hose which was about collapsed and the thermostat. Didn't make a whole lot of difference. Some one told me 454's tend to run warm. Do they???

Which hose did he change, the lower radiator hose? If it was the radiator tubes being restricted from plugging will cause the lower hose to collapse. Another thing can cause over heating. Restricted air flow through the radiator and dash AC condenser fins plugged by dirt, leaves, pet hair, etc. Also a bad fan clutch will cause over heating. You need to determine if your gauge is reading correct. Unfortunately your coach 1991, chassis could be older is not an ODBII compliant so the Scan Gauge will not work. Your mechanic should be able the check the temperature at the thermostat housing with a IR temperature gun. Also have him check the temperatures across the radiator to see how well it's removing the heat. Both will need to be done while driving the coach, so he will need some assistance to do it. If he determines the radiator needs to be pulled and cleaned have all the other cooant hoses changed if they haven't been changed in five years.

Chuck

Fl_Richard · 07-16-2014, 05:32 PM

195 and rarely deviates. Even with electric booster fan running. That's in SW Florida in July.

BA-in-Mich · 07-16-2014, 06:45 PM

Recore or replace the radiator. Before I had mine recored I put a 180* stat in it. It still ran over 200* after recore 180*. Nuff said.

Tha_Rooster · 07-16-2014, 07:28 PM

I had one that the exhaust manifold cracked and was blowing hot air on the temp sensor which showed it hotter than it was eventually melted it. I understand that was a common problem also had the bugs cleaned out and from in between the 2 radiators replaced electric fan changed clutch on engine fan which finally fixed it.

1972VWbus · 06-20-2022, 10:18 AM

Quote...

"Your temperature should not deviate much from the temperature of your thermostat.

If you have a 195 I would be concerned if the temp went over 210 climbing a hill in hot weather.

If it does I check for a dirty radiator, glazed fan belt and then the thermostat itself.

-Tom"

Oh boy, that is not how a functioning cooling system works. During the TBI years it was normal for a 454 to run 210 - 240. The dash gauges in those years were not very accurate (read higher as much as 20-40 degrees).

What helps?

Keep the engine in 'peak tune' and coolant system in order. Run a 60 percent distilled water vs 40 percent coolant ratio.

Dan_Frisbie · 06-20-2022, 10:52 AM

While you most likely have a cooling/fluid/guage problem, don't discount fuel.If you are running too lean, then you are creating a lot of heat in the engine combustion chambers. Since you don't disclose what year, I'll offer this;
If it's carbuereted, the issue could be timing, carb jet size, or just carbueretor condition, but I doubt that...
If it's fuel injected, the computer is giving erroneous data for some reason. I had a low compression cylinder on a 1995 Chevy with TBI, the 02 sensor saw a lot of carbon (burned oil) in the exhaust and kept trimming the fuel flow back. Truck ran hot and woud even starve on a steep hill.

House Husband · 06-20-2022, 05:17 PM

Some of those old 454 P32 coaches just barely had enough radiator. Many owners bought radiators with an extra core to keep things cool.

Richard

Skip426 · 06-20-2022, 11:22 PM

Original post is 8 years old .
OP last active on site 5 1/2 years ago ; and before he was last on site , he changed his coach from his 454 powered gasser , to a diesel pusher and up dated his signature line .

JMHO : I don't believe this particular thread requires any more posts .