Problem 1:

When the car gets very hot at the track, some coolant flows to the overflow bottle. I was told that the radiator will automatically suck back the excess coolant from the bottle when the car is totally cooled down. This doesn't happen. I have a C&R radiator, tried both Slant 19-21 psi and Spoon 1.35bar rad cap, new coolant, bleed properly, checked leaks everywhere (none). The car is fine when the rad is full of coolant, just overheats when some go over to overflow bottle and not returned back when the car cools down. Any comments?

Problem 2:

I just had a clutch-type LSD installed in the tranny. Every works fine except it makes a "squealing" sound only when turning the steering wheel left while the car is in motion. No sound is heard when the car stops. Any idea?

 

Damn!!!
Well for prob 1 check your thermostart and water pump and make sure your fans come on.
As for problem 2 not sure but check your axles.

 

#1
Yes, its supposed to go to the overflow bottle, then get sucked back in when it cools down. The radiator cap controls that. Not the thermostat or fan switch. Check how the cap seals against the neck of the radiator. There's 2 places on the neck that seal. There's a third seal that's just in the cap, that opens up to suck liquid back into the radiator. If the top one (largest diameter rubber gasket in the cap) leaks, then it'll suck air back instead of sucking coolant. Could be a bad gasket or maybe the top surface of the radiator neck isn't smooth.

Also check the hose over to the bottle. If it has any leaks that's like drinking thru a straw with holes. You just get air, not liquid... You can probably check that with a MityVac.

I don't know about #2...

 

#1
The rad is new so I don't think that's the problem. I've tried 2 new rad cap so I don't think that's the problem either. I've checked the coolant reservoir hoses, but I'll do it again with a MityVac to make sure.

#2
I've heard maybe to check the upper ball joints and tie rods. Can these cause any sound? What about the driveshafts?

 

Maybe you have some air in your coolant lines?

 

#1
With the cap still in place, attach the MityVac to the bottom end of the reservoir hose. The end that's supposed to sit submerged in antifreeze at the bottom of the reservoir. The vacuum will probably flatten the hose, but there shouldn't be any leaks.

#2
Sounds like the LSD itself. If it were ball joints or tie rods it should still make the noise when you steer without moving. Driveshafts - maybe? Don't they usually make clicking or klunking sounds?

How about brakes? Once when my brakes were almost gone the wear warning finger made a moaning sound only in reverse, and not when I applied the brakes. It sure didn't sound like the fingernails-on-chalkboard sound that they usually make.