LS Swap Engine over heating

donnie1956

Active member
Joined
Oct 22, 2011
Messages
32
Location
Troy,MO
Finally got most of the all bugs worked out on my LS swap except it overheats. When cruising around 60 mph or so it would run around 200 or so. If I drove a little harder the temp would run up to 240 and keep climbing until I let off and backed of to 60 mph.
Made sure all the hoses were in good working condition. Installed a new radiator cap. New alum radiator since swap, Both electric fans work and turn on when they should, made sure all the foam seals were in place and the lower air spoiler is installed.
Finally removed the t stat and the temp dropped to less than 190 and with aggressive driving it will climb to 220. Currently running on water and no T stat.
Something still doesn't seem right with my set up, Ran across this forum tonight and discussions about overheating with turbo's, but still some good information about how LS water pumps operate differently than SBC or BBC.

http://www.yellowbullet.com/forum/showthread.php?t=621363

This got me thinking that is it possible my vintage air system with the heater bypass valve closing adding to overheating problem? Going to install a new t stat but hesitant to dump more antifreeze in until I get the problem figured out.
 
Steam port?

I noticed that the poster had linked over to the Pirate 4x4 website. That site has a lot of good tech info on it!!! "Billavista Tech Garage" is well done.

How did you handle your steam tube/port- since in the C3 the radiator for the most part is lower than the engine.

I used an aluminum tube - inline in the top rad hose- the highest point in the system for my steam port- after seeing how a guy on Pro-Touring had handled it-

16916735308_42f87efc28_h.jpgDSCN5129 by Richard Hayes, on Flickr

A solution I saw over at Pro-Touring Website-

DSC_8061_.jpg
 
I'd require some convincing to believe that is working like it should. While it would blurp steam out, it wouldn't prevent an air pocket in the system from locking up the cooling system. If you used a closed-loop air-removal system, there cannot be any restrictions on that system.
 
Steam Vent Routing

Your routing is suspect.... instead of purging air to the radiator to be eventually eliminated, you have hooked into the puke side of the cap. So really causing 2 problems!
 
Donnie,

FWIW, I went from the mechanical fan to a dual electric fan setup and she seemed to want to run hot, but did it mostly at lower rpm/speed.

The general consensus seems to be that when running hot at speeds above 35 mph your rad is too small.

I just installed a third relay to run the fans continually in series and only when the engine temps hit a certain level (205°F) the fans are switched to parallell use and high speed. I found out that this is necessary as our cars do not create as much low pressure below the car as you would think. Combined with the heat from the exhaust etc in the cramped engine bay, creates a higher pressure which makes it difficult for the air to move through the rad on its own.
 
Donnie,
I'm with EE on that. If that's the overflow port on the thermostat cap, it should be connected to a non pressurized reservoir.
The steam vents should be connected into the pressurized cooling system. I tapped a port on my water pump. If you want to check mine out, let me know when you'll be in my area.
As for the non bypass HCV, I'm not having issues, but heard from others that have. There is a 4 port bypass electric HCV for Lincolns you could try. But would suggest you get the cooling routed correctly first.
 
Here is a better photo of current set up which is wrong. Steam plumbing needs to go inline with upper hose not in same line as expansion tank. Will never get all the air out of system like this. Going to pick up some fittings and re plumb the expansion tank.
20Swap%20Top%20hose%20plumbing%20wrong_zps7svhtasp.jpg
 
I don't think it will work properly like that.

The cap is on the hot side in your system. It needs to be on the cold side. The reason is this : when coolant heats up, it builds pressure. When it cools it looses pressure. You want a minimum of 15 psi of coolant pressure, but that's the pressure on the low, cold side of the system.

In your system you will loose pressure when the coolant cools in the radiator. It will not be at 15 psi anymore, but maybe half that.

The pump pulls a lot of coolant through the rad at high speed. It creates vacuum in the lower hose (cold side). If the pressure is already low there, it will cause the fluid to flash to steam at temps below 100°C. This first creates cavitation and later on the pump will not flow any fluid anymore.

maybe there is a custom rad for this setup, with the hot side on the right and the cold side on the left...

I don't know about the steam circuit in that engine, but I don't think the low rad placement would cause any problems if the cap is working fine.

My suggestion, throw that piece in between the top hose out and connect it directly to the radiator and use a proper cap on the radiator connected to the regular vette bottle. See how it does.

My .02$

PS : regular water will cause issues with your alu motor.
 
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I'd lose the second rad cap-and just have one on the radiator- w/ something like this-

hk28116-lower-radiator-hose-connector-1-3-4.jpg


or this-

$_3.jpg
 
Changed plumbing

I have changed the routing of the steam fitting by drilling and tapping into side of the body of the upper radiator cap. I need the 2nd radiator cap as the way the plumbing works out the upper hose is above the radiator, this lets me vent the air out of the system. The lower radiator cap is rated for 16 lbs and the upper one is rated for 12 lbs. The upper small hose under cap is vented to expansion tank. Would be another major pain to change the water pump neck to be lower than the radiator and to get a different radiator. Still need to install the thermostat but so far no over heating. Need to get some good interstate driving in to prove it out.
Looking back I would have changed the angle of the upper water pump fitting and had the radiator necks on the passenger side of car. Hose routing would have been shorter and simpler.
 
Are both the radiator cap overflow fittings T ed together and routed to the overflow reservoir?
I'm not sure on cool down if the lower pressure cap will preferentially suction in from the reservoir.
 
The vent hose from both radiator caps tees into the expansion tank. Installed the new thermostat and ran it pretty hard plus about 10-12 miles of freeway at 80 mph and temp was around 210-212. Combination of problems.
 
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