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Chow5656 · 05-31-2013, 06:43 PM

Shroud ill make a huge difference esp sitting still. Water will actually run cooler than antifreeze. Antifreeze holds heat. No thermostat will make it run hot going down the road... Water goes through the rad to fast and doesn't cool.

Jarog · 05-31-2013, 06:47 PM

Quote:

Originally Posted by Chow5656

Shroud ill make a huge difference esp sitting still. Water will actually run cooler than antifreeze. Antifreeze holds heat. No thermostat will make it run hot going down the road... Water goes through the rad to fast and doesn't cool.

Here's a curious question. If water boils at 212f. Why isn't the radiator boiling over?

Jarog · 05-31-2013, 06:50 PM

Beginning to also question the accuracy of my temp gauge. With inferred thermo where should I take a reading?

Chow5656 · 05-31-2013, 06:52 PM

Quote:

Originally Posted by Jarog

Here's a curious question. If water boils at 212f. Why isn't the radiator boiling over?

Pressure cap helps keep that from happening

singpilot · 05-31-2013, 06:54 PM

OK, couple of things.

No thermostat (I know this sounds funny) will allow hot water to not stay in rad long enough to cool. Unrestricted flow could also be making the water pump cavitate when at high rpm.

ALL thermostats (new and rebuilt) (how do you 'rebuild' a thermostat) are from 'south of the border'. I actually saw one on a recent 'quest' along these exact same lines that said "Hecho in PRC".

I have gone thru 3 before getting a good one. YMMV.

I had a 'rat 454' motor from a bad radiator come in with all of the jackets and passages plugged with rubber 'turds'... compliments of some 'leak stop' crap.

I hate to say this, but water pumps these days are also 'hecho'ed' poorly. Did you change the pump? Are the vanes pointing the correct way?

If the shroud is not on, that alone could be contributing.

Let us know what you find.

Jarog · 05-31-2013, 06:55 PM

Quote:

Originally Posted by Chow5656

Pressure cap helps keep that from happening

What about the overflow? Not being a smart a$@ just wondering.

Brockx · 05-31-2013, 07:05 PM

Quote:

Originally Posted by Chow5656

Pressure cap helps keep that from happening

X2

The higher rated the pressure gap the hotter it can go with out boiling. A good trick is if you have a hose leak, tape it and run the cap loose until you can get to help.

Brockx · 05-31-2013, 07:11 PM

Quote:

Originally Posted by Chow5656

No thermostat will make it run hot going down the road... Water goes through the rad to fast and doesn't cool.

I had always heard that and saw proof a couple of times, didn't want to post it as a definite, glad you did

.

lx22 · 05-31-2013, 07:12 PM

You have a either a lean condition or a clogged exhaust system. You need to have them checked out by a reputable shop.

BFlinn181 · 05-31-2013, 07:30 PM

Quote:

Originally Posted by Jarog

What about the overflow? Not being a smart a$@ just wondering.

The overflow takes coolant that pushes up the inside seal on the pressure cap a bit and it diverts into overflow tank. Put the shrouding back on, the thermostat in, and then take it for a ride. The faster you go, the more air has to be pushed out of the way, the engine works harder and burns more fuel, i.e. more heat.

Jarog · 05-31-2013, 07:46 PM

Quote:

Originally Posted by BFlinn181

The overflow takes coolant that pushes up the inside seal on the pressure cap a bit and it diverts into overflow tank. Put the shrouding back on, the thermostat in, and then take it for a ride. The faster you go, the more air has to be pushed out of the way, the engine works harder and burns more fuel, i.e. more heat.

I think we're on the same page and your answering my question. I guess these things push so much air when traveling at 65 70 mph that they are naturally going to run warmer.

wb7auk · 06-01-2013, 09:10 AM

Quote:

Originally Posted by Jarog

Ya think ? Shouldn't I see oil and water mixing on the dip stick?

Not always, there is two ways to check take the rad cap off and have the engine at high idle and look for bubbles in the coolant, second they have a test fluid that turns color if the cooling system is getting exhaust gases.

steveclv · 06-01-2013, 11:13 AM

My 1984 Monaco had the 454 carb engine and always ran hot and was designed to do so for emissions - spec was 225 and 240 was acceptable.

However, as road speeds have increased over the decades, I found that the a good size hill would bring it over 250 and that was too high for me to feel comfortable even though I was told that it was perfectly normal.

I ended up going to a 5 core radiator instead of the original 3 and it made a huge difference. If you do go this way, they use the 195 thermostat with it.

After I did that, I could run full throttle up a long hill and still keep 240 at the top.

Of course, I also replaced all of the vacuum lines and made sure that the distributor weights were free to move and lightly oiled.

wb7auk · 06-01-2013, 11:42 AM

All of these big block engines installed in MH run way to hot and results in anything
made of rubber not lasting very long as well as broken exhaust manifolds ect.
As stated above going from a 3 core to a 5 core helps a lot as does replacing the
thermostat to one in the 180 or 195 degree range.