1985 345 Major Overheating issues

[bkahler]

As Wayne stated the 454 powered motorhomes I'm aware of have the engine temp taken on the drivers side head. That location will always read higher than other locations. I prefer to always verify temperatures using a non contact laser infrared temperature gun.

It sounds to me like your temperatures are close to normal if you're getting 175 to 210. Although the 210 might be a little on the high side. Does the 210 show up while driving or at idle? If at idle then you still might have something to worry about.

Like Wayne I will have multiple temperature sensors on the engine. I'm will actually have for sensors, one in each head, one at the top front of the manifold and one close to that for the PCM to use. I plan on having a switch that will allow me to toggle between the first three. No special reason for having this many other than I had them available and I thought it would be an interesting way to monitor engine temps

Brad

[Toddnazus]

Hey Folks,

Looking back, its been a LONG time since I first posted this... we have solved ALL our overheating issues. There were a number of solutions we applied along the way, so in order to "put a bow" on this thread, I'll list off all of our solutions.


1) Custom Aluminium radiator
2) Installed 4L80E 4 speed transmission (this took a while to get programmed correctly, but once properly wired, works fantastic)
3) Installed Secondary Transmission cooler (in addition to radiator cooling)
4) Installed Oil cooler
5) Installed dual electric cooling fans mounted in front.
6) The Kitchen Sink....

MOST of the delays in the transmission resolution came from us using a Transmission shop that had no idea/business working on an RV. (+1 year of repairs).

Thanks all for sharing your thoughts and ideas throughout this tread.

Todd

[davejay]

Hey,
I've been thinking about you all day. Let's back this up a little. You got 35k on this unit. It's been running fine, until this trip. What were you doing when you noticed the temp going up. A454 should be able to handle a pretty good amount of abuse. So, we're you pulling a long uphill grade, were you bucking a big head wind?
I say this because you don't just blow a gasket tooling down the road. Something triggered this. Did you just fill up with gas? Maybe you got a bad slug of fuel. You say you blew a valve cover gasket. Did you mean a head gasket, or a valve cover gasket. If you blew a valve cover gasket, that implies lots of internal pressure. Going down hill will create a lot vacuum. You have a pcv valve on the valve cover to suck any internal pressure off the engine. If it closes up or sticks you get pressure on the engine. The pcv is routed to the base of the carb, and all of that pressure is routed to the intake.
Anyway. Is it possible you have a master cylinder that is sticking. Thus causing your brakes to drag? If you were going down hill, and were on the brakes, as brakes get hotter they swell and then start to drag. Engine works harder to keep the unit moving. Temps go up. If the brakes cool. It all goes back to normal. If the master cylinder is hanging up. Then the brakes are still engaged.
Did it feel like the motor was laboring, like you were in a big head wind?
Once the unit cools down, the brakes cool down, the master cylinder may act perfectly normal again, until you heat the brakes up. Then, this whole thing starts again. That's why I asked what were you doing when you noticed the temp rising.
Just thinking about this. You got a weird scenario here. DJ