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240 LS swap cooling system thread

I run the lingenfelter 165 thermostat and my car sits at about 190 all the time regardless of weather or traffic. If I hammer it for a long time it sometimes will hit 210 on the gauge. But logs have never shown much over 200
 
Running into temp issues with the LS- my fans have no shroud. I vacuum-filled to purge air, still goes to 210 while idling.of course this was in 100* ambient temps.This is with NOS 240 diesel radiator. I have clearance issues with single 940 fan, so I am running twin 12” Mishimoto fans. I am installing a 160* thermostat and want to get some kind of shroud. Maybe fans with more cfm.
 
Sorry to tell you this. But those damn mishimoto fans are completely junk, they do not flow near the cfm the advertise. Also they draw only about 5-7amps running. I had 2 on my Hilux with the b21ft and it would over heat so bad in traffic. Switched over to a derale fan and never had a issue again
 
I had my radiator custom built when I did my V8 swap 30 years ago. Heavy duty 4 core with brass tanks, the core opening is as big as the opening on the car,17"H X 24"W, 2 12" pusher fans with a thermo switch and a manual override, I run a 180 thermostat to get enough heat in the motor,and a remote expansion tank. Never ever had a cooling issue. The price in 1988,$ 375.00.
 
After talking to JohnMc at the Mountain Meet, I ordered the LOJ heater bypass valve. I think that no flow through the heater hoses when the heater valve is off is contributing to my cooling issues.
Thanks, John!
 
MikeSr. said:
Running into temp issues with the LS- my fans have no shroud. I vacuum-filled to purge air, still goes to 210 while idling.of course this was in 100* ambient temps.This is with NOS 240 diesel radiator. I have clearance issues with single 940 fan, so I am running twin 12? Mishimoto fans. I am installing a 160* thermostat and want to get some kind of shroud. Maybe fans with more cfm.
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Lower temp t'stat won't solve the problem - might buy you a bit more time before temp rises. If the system won't reject enough heat to keep it below 210F, how is it going to reject the additional heat needed to keep things at 160F? Issue is likely not enough air flow as mentioned above. Once that's solved you'll find out if the stock rad has enough capacity to deal with the extra thermal load.
 
I’m pretty sure the NOS diesel radiator will work. That LOJ valve should solve some of my issues- apparently with no flow through the heater hoses, the water pump cavitates and causes overheating. I talked to some hot rod guys who recommended the 160* thermostat, even suggesting drilling a couple of 1/8” holes to bleed air. Saw a ‘69 Camaro with this setup and a huge BeCool radiator with dual fans. Owner says even with this setup, gets to 210* idling in traffic. His motor was iron block- my aluminum block should cool better. Gonna look for a Lincoln MkVIII or Mercedes C class fan=4000 cfm.
 
With a 187F t'stat (oem LS3) at the engine inlet, mine sits right at 196F (head temp sensor) as long as I'm moving fast enough to keep the fans off. If the fans have to come on, it sits right at 203F (fan control point on mine) regardless of load/speed/ambient/ac-on or off. If you have enough fan and enough rad capacity -- temps should be controlled by the t'stat and the fan control set point. I used a couple of Dorman T's to create a small (1/8") bypass for the t'stat. That's mainly an issue on cold start to warm up -- once at operating temp, it has no impact.

FWIW - I use the fully shrouded SPAL dual 11" fan set up. 15 years now. About as "thin" as these set ups get. Moves plenty of air. OEM supplier to many. And doesn't pull nearly as many amps at full speed as the Mark VIII will. If your rad is new - then this is probably not the issue. But Testpoint had overheating problems with his 5.0L and diesel radiator. Turned out the old diesel unit had about the bottom third non-functioning due to deposits. Re-cored - solved the problem.
 
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Yeah- my radiator is NOS. I tried the dual Spal fans, but had a clearance issue. I might try a 16” slim brushless fan if I can’t find a MkVIII.
 
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MikeSr. said:
After talking to JohnMc at the Mountain Meet, I ordered the LOJ heater bypass valve. I think that no flow through the heater hoses when the heater valve is off is contributing to my cooling issues.
Thanks, John!
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I was gonna say the ls overheats when you have the heater control valve on cold
 
MikeSr. said:
I tried the dual Spal fans, but had a clearance issue.
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I feel your pain - when I had the 5.0L in mine, had about a credit-card's-width clear between idler pulley and one of the fan motors. Solved that with the LS using Corvette pulley spacing - got a good 2"-2.5" clear on this one.
 
I certainly have no direct experience with it (yet), but I've just read that the LS needs coolant flow through the heater piping. Because otherwise, hot coolant might not get to the thermostat (or at least not very well) if it's closed all the way.

Mostly an issue (I've heard) on initial warmup.
 
And tons of folks have no bypass at all and report no problems at all. Whatever issues it might cause are not universal. I put one on mine simply because the factory saw fit to do it - good enough for me.
 
A modest/small hole in the thermostat probably works about as well. The thermostat is just stuck out in the waterpump, not in close contact with the head or block. If it's not moving coolant *at all*, it just has to slowly heat up by conduction, out from the head, over to the side, to the thermostat.
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Actually, drilling a little hole is also said to be a good idea to get air/steam out of the system as well, plus it probably does about the same job in keeping coolant flowing by the thermostat when it's closed. And probably less of a hassle than trying to fit some sort of recirculating valve into the heater system.

It probably also encourages a much more even warmup. Volvo thermostats open a passageway between the two sides of the cooling system when they're shut. So coolant circulates around under pressure from the pump, inside the block. From the areas that get hot soonest to the ones that don't.
 
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I may have drilled a hole, but I fo sho didn't put a coolant bypass on it. Then again, iirc the heater valve that I'm using doesn't fully seal anyway because it's a cheap piece of ****--that doesn't leak. so... who knows. bleeding the system is a pain in the ass fo sho though.
 
Well, my heat problem may be a combination of air, heater hose flow restriction and inadequate fans. I raised the front end and cracked the steam lines until coolant came out. No change.Then I got a vacuum filler and tried to get the air vacuumed out. No change. Next will try the bypass valve, then a bigger fan/shroud.
 
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