Custom-Musclecars

After a few obstacles we finally got our LT1 to LS1 conversion done. The current issue is the cooling system. To start off, the engine is a 2002, rebuilt, all new vette accesories, 98 PCM and wiring, new 160 tstat, and a Griffin aluminum radiator with flexalite electric fan/shroud made for the 1st gen camaro, autometer temp sender in r/r cyl head, new pcm temp sender reading close to the Autometer gauge. It seemed to run cool with the LT1, but the guy had the temp sender on the output of the tstat, so it wouldnt read unless the tstat opened. I have seen people do LS1 conversion cooling systems using the hose coming out of the thermostat to connect to the bottom of the radiator (passenger side) and the other hose (inlet) connected to the top (drivers side) of the radiator. This seemed to work for a little while, with temps generally around 180-190 until you let it idle for a long time then it creeps up to 210-220, the radiator is pretty cool, and the air from the fan is cool. If you rev the engine to over 1200 rpm, you can feel the heat going into the radiator and it starts to cool down. So we switched the hoses, tstat to top, other hose to lower, and it keeps burping air in the radiator, but wont cool down. Im thinking about removing the tstat to get more flow at idle. Any other suggestions??? Otherwise it runs like a bat out of hell for a Chevy

i885744

Sounds odd, could be a bad thermostat, is the water pump new? The same thing also happens when there is a major clog in the cooling system, ie a very rusty radiator or something. The hose that connects to the thermostat housing should go to the lower port on radiator, one that comes straight out from the block goes to upper.

72ChevelleConv.LS1

iTrader: (5)

I Just went through my ls1 and when I put it back in my car and went around the block the temp went up to 220F My car runs at 180 F all the time. this was way too hot for my LS1. I asked my freind who does a lot of LS1 stuff and he said I didnt have the air blead out good enough. said they are real hard to bleed. Steps are as follows... Remove the rad cap , start the car, run the motor up to 2000 rpm and wait. the coolent will start comming out of the bypass tube on the top of the block. once you see this, you can put the cap back on the radiator and test drive it. My car had a lot of air in it. after I completed this the car ran at 180F again.. Good Luck!

vtanju

iTrader: (2)

hi,

removing the thermostat will not do you any good unless you close the round opening inside the waterpump, on which the bottom of the thermostat sits and covers. check to see if you have any combustion chamber pressures leaking into the cooling system.

hope this helps

Stu Cool

iTrader: (13)

One thing I was told to do is fill the radiator through the upper radiator hose instead of the radiator cap. This prevents air locks from forming in the heads. Do you have the air bleed hose from the heads connected somewhere?

Pat

Custom-Musclecars

OK, I tried what 72Chevelle said and alot of air did come out of the tb coolant tube (capped off on the tube) It took more coolant, then starting cooling down. We went for about an hour drive and didnt get over 185 unless you were sitting in traffic for a few minutes at an idle. As soon as we got moving, it cooled back down from about 210 to 180. It doesnt ever build enough pressure to pop the cap, so Im assuming the head gaskets are ok. I know the LS6 has the throttle body coolant tubes blocked off, but since I have the tubes on my engine, should I connect them to the radiator someway, or just leave it capped off?
Thanks!

vtanju

iTrader: (2)

block the ones in the rear, and direct the front ones back into the radiator, and if the car is not overheating while driving but overheating in trafic, i would think that the fans are not good enough.

Stu Cool

iTrader: (13)

There are a number of ways to route the coolant tubes into the main cooling system. You can get a tee fitting from Jags That Run (http://www.jtrpublishing.com/index.html) to put into your radiator hose. Some of the GM Trucks have them run into the heater hose. On my car I drilled and tapped a hole in the top of the water pump and put a 1/8 NPT fitting there and connected it to that. Very compact and mostly out of site. You do not need to run it through the throttle body, that's only for cold weather climates. Here is a picture of mine into the water pump.

Speartech

iTrader: (14)

That's a GREAT way to do it! Simple and effective.

72ChevelleConv.LS1

iTrader: (5)

I would connect them. Oh yea I forgot to say that your enging should be on level ground when doing this.. Glad it worked..