53 chevy on 95 s10 frame cooling issues

[altereddezignz]

Hello everyone. So we finished up our project and have had some cooling issues. Here is where i am at and what the issues are.
53 chevy 5 window
95 s10 frame
Radiator link is below.
165 Degree thermostat
15" electric fan on engine side
vintage heat and air so truck has an ac condenser
Texas speed small cam
small stall
stock motor other than cam and stock trans other than convertor
Trans cooler with electric fan mounted to the frame.
Shorty block hugger headers
2.75 exhaust.

Issues when we changed setting in shop truck will heat to 185 and kick fan on then cool to 175 and shut fan off. This is how the computer is set up. Drove truck to at 60 degrees outside and truck got to 200 setting at stop light with fan running then will cool off some when driving. It was back at 174 when we got back to the shop. Not sure what the issues are. Almost 1000% sure there is not an air pocket. ECU coolant temp says about 6 degrees off what the gauge says. Fan kicks on at 185 off at 175. Does have antifreeze in it. We filled the radiator with the heater core valve open and heat does blow very hot inside so we know there is water moving. You can remove cap and water is rushing by in the radiator. Truck runs great other than this issue..

Any ideas.. Thanks. Oh with the factory 195 thermostat truck would hit obove 225. We moved the radiator back and ac condincer forward and let us put the fan between the motor and radiator. At that same time we also changed to the 165 thermostat.
Truck does not miss, runs good, no water in oil and no moisture in exhaust. No loosing water, no leaks, Good compression. So im at a loss..

http://www.northernfactory.com/HIGH_...DIATORS/205156

[HUSSEY]

I can't figure out why it would run hot while sitting and not while driving other than either poor coolant flow or poor airflow.

What CFM fan are you running? Does it seem like it moves a decent amount of air? Is the air coming out of the fan seem fairly hot?

I know you said there was good coolant flow in the radiator but are you sure you have the appropriate water pump pulley diameter? That could effect the flow. Or, just making sure nothing is wrong with the pump like a badly corroded impeller.

[altereddezignz]

It may have been in the mid lower 50s in the shop the other night when we ran it. But factory pump pully. I don't know the cfm off my head but it seems to move a ton of air and the air moving off the fan is very hot. Before we put motor in I looked around inside the water pump to make sure there was no corrosion. Also the radiator that came off the truck was very clean and coolant was clean.
Changing the thermostate helped a lot but I don't think as much as it should for it be in a 165. None of the hoses are really sharp bends. Nothing kinked. Upper house is a long arch. Bottom hoes is an sshape but it's only about 8 inches long but it has hart tube inside it for all. It the turns.

[mongocanfly]

I can't tell from pic but is that a ls engine? If so you probably have a air pocket in the engine..remove top radiator hose from radiator and fill the block as well as the radiator with coolant..make sure to fill it until no air bubbles come out..reattach hose..

[OrrieG]

Upper radiator hose looks suspect, no way to bleed off the air with the arc in it, needs to at least flat and below fill line. Other issue is probably air flow thru the condenser and radiator, fan may not be pulling enough air when truck is not moving.

[altereddezignz]

Tremendous amount of air flow through the radiator. He drove it a few minutes ago. I may try the hose radiator thing.

[mongocanfly]

Air flow means nothing if you've got air trapped in the engine..is it a LS engine?

[altereddezignz]

Yes it is an ls engine. The bleed line that normally goes into the throttle body was left unplugged until after the truck had ran for a good while and that we had a normal steady flow of water coming out it. Now not saying there may not still be some air in it but I have had air locked ls engine issues before. But I never thought about the upper radiator hose being arched above the radiator.

[dsraven]

check out this link to a 4x4 and dune buggy site. the write up explains a lot about the ls cooling system. it doesn't work the same way as the old style small block stuff because the thermostat is at the water pump inlet instead of at the engine outlet, or upper rad hose, area. there are bypass circuits built in etc, anyway, the write up explains a lot and may help you fix the problem. highlight the address below, right click on the blue text and choose "go to pirate 4x4..." or type this into google and grab a cup of your favorite beverage. it is a bit long winded but explains, in detail, how the system works and what it requires for proper operation. the site is for 4x4's and dunebuggies that work in the hot sand dunes so they must have something right.another great thing on the site is a good history on the ls engines and their changes over the years.good luck.

http://www.pirate4x4.com/tech/billavista/Cooling/

[dsraven]

or just click on the link, duh on my part. sorry.
if you check the tech articles there is lots of interesting reading on that site as well.

[Jesse Z]

Originally Posted by OrrieG

Upper radiator hose looks suspect, no way to bleed off the air with the arc in it, needs to at least flat and below fill line.

Bingo. I've had nothing but overheating trouble when I've had radiator hoses higher than the radiator.

[Elder Rogue]

I know this is going to sound strange, but check the specs on the engine for the stock thermostat. If it calls for a 195 and you put in a 165 the stat could be holding open all the time and the coolant is rushing through the system too fast and not having time to displace heat properly in the radiator.

The pirate 4x4 article says this is a myth but it was the cause of my cooling issue in a 36 PU with 327 V8 and Walker Radiator, so I am not talking from something I hear or read on the internet, just sharing my experiences

Your results my vary

[dsraven]

the 327 v8 had a different cooling system than an LS engine has. the LS thermostat controls coolant RETURN from rad rather than OUTFLOW from engine.

where does the steam line from the heads go? through throttle body and then where? it is hard to make out in the pic. possibly a few more pics or details would help us help you figure it out?

is the rad cap the highest point in the cooling system?

what have you got for a surge tank set up? is it a true surge tank or an overflow tank or does the overflow hose from the rad cap dump onto the ground? is it possible to install a true surge tank near the rad somewhere and still keep it under the hood? possibly a surge tank from a p/u or corvette that came with LS that has a rad cap on it-just keep the rad cap on the rad as well to operate as a plug? possibly a custom tank like the pirate 4x4 article? it is an integral part of the system to de-aerate the coolant. possibly your problem with overheating?

maybe read the entire article and see how it can be applied to your truck, before it is too late and something overheats too far. I know, nobody likes to read all that stuff or redo anything that has already had a whack of thought put into it, but if you continue to overheat you may be redoing the engine and THEN fixing the overheating issue. remember, they don't work the same as the old small block engines. plus you are running a downflow rad, which isn't optimal for an LS engine.

keep us posted