Deleting the coolant crossover tube??
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Joined: Oct 2003
Posts: 2,140
From: DOVER DE
Re: Deleting the coolant crossover tube??
It allows steam to exit the heads, without it you will get hot spots in the heads as air is traped and can't get out. It's there for the same reason GM put the small steam holes in the 400 SB heads. Leave it on.
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Joined: Jan 2003
Posts: 771
From: Houston Tx
Re: Deleting the coolant crossover tube??
The LT1 has strategically placed steam vents at the back of both cylinder heads. Since the heads are the hottest part of the engine, pockets of steam can be more easily generated there. The steam vents are connected together by a crossover vent tube at the back of the heads, which directs any steam and a small flow of coolant to the front of the engine where it flows through the throttle body, warming it for improved cold weather performance. After passing through the throttle body, most of the steam is condensed back into liquid coolant and returned to the system.
In LT1 B/D-cars, coolant exiting the throttle body is passed directly into a pressurized coolant reservoir where any air remaining in the coolant is completely scavenged. In LT1 F-cars, coolant from the throttle body connects to the heater outlet via a vented "tee" connector, where any trapped air in the system can be bled off manually. Eliminating steam pockets and foam in the coolant allows for more uniform cooling system performance, preventing hot spots and potential overheating.
got that from a info site.
In LT1 B/D-cars, coolant exiting the throttle body is passed directly into a pressurized coolant reservoir where any air remaining in the coolant is completely scavenged. In LT1 F-cars, coolant from the throttle body connects to the heater outlet via a vented "tee" connector, where any trapped air in the system can be bled off manually. Eliminating steam pockets and foam in the coolant allows for more uniform cooling system performance, preventing hot spots and potential overheating.
got that from a info site.
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Joined: Mar 2000
Posts: 1,955
From: Point Pleasant, NJ... USA
Re: Deleting the coolant crossover tube??
Originally Posted by dnz28
The LT1 has strategically placed steam vents at the back of both cylinder heads. Since the heads are the hottest part of the engine, pockets of steam can be more easily generated there. The steam vents are connected together by a crossover vent tube at the back of the heads, which directs any steam and a small flow of coolant to the front of the engine where it flows through the throttle body,
[This is only true for 95-7.. for 93-4 it goes directly to the radiator..]
warming it for improved cold weather performance. After passing through the throttle body, most of the steam is condensed back into liquid coolant and returned to the system.
In LT1 B/D-cars, coolant exiting the throttle body is passed directly into a pressurized coolant reservoir where any air remaining in the coolant is completely scavenged. In LT1 F-cars, coolant from the throttle body connects to the heater outlet via a vented "tee" connector,
[This is only true in 93-4 cars... 95-7 have no such 'tee'..]
where any trapped air in the system can be bled off manually. Eliminating steam pockets and foam in the coolant allows for more uniform cooling system performance, preventing hot spots and potential overheating.
got that from a info site.
[This is only true for 95-7.. for 93-4 it goes directly to the radiator..]
warming it for improved cold weather performance. After passing through the throttle body, most of the steam is condensed back into liquid coolant and returned to the system.
In LT1 B/D-cars, coolant exiting the throttle body is passed directly into a pressurized coolant reservoir where any air remaining in the coolant is completely scavenged. In LT1 F-cars, coolant from the throttle body connects to the heater outlet via a vented "tee" connector,
[This is only true in 93-4 cars... 95-7 have no such 'tee'..]
where any trapped air in the system can be bled off manually. Eliminating steam pockets and foam in the coolant allows for more uniform cooling system performance, preventing hot spots and potential overheating.
got that from a info site.
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Joined: Feb 2004
Posts: 4,800
Re: Deleting the coolant crossover tube??
All the LTX motors have it as does the L99(4.3L V8 base motor in the 94-6 Caprice which looks exactly like an LT1). One guy on the Impala board bought a modded car(LT4 heads and such) only to find the coolant crossover deleted, best we could figure was the old owner took the TB coolant bypass a bit too far, either way once the guy put a crossover back on the car he said it felt MUCH better. Delete it and I guarantee that you will get detonation from hot spots in the heads, the detonation will cause retarded timing and reduced power, heck maybe even damage if it is bad enough.
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Joined: Sep 2002
Posts: 333
From: Palm Bay, Florida
Re: Deleting the coolant crossover tube??
Guys, you cannot take that steam tube off. It's not really a "steam" tube, although everyone calls it that.
All SBC's have had a crossover between the heads that takes the hot water (hot water rises) from the top section of the heads and sends it back to the radiator. The older SBC's had it on the front of the intake manifold and the thermostat would be mounted where it came together. On the LT-1, the thermostat is on the waterpump and the intake manifold is dry, so they still need to get the hot water out of the heads. The "crossover" takes the water from both heads and brings it back to the radiator. Gm decided to route this through the throttle body for heating it up, but if you do the bypass you should connect the hose from one side of the TB to the hose on the other side so the water can still get back to the radiator.
If you want to see how much water actually flows, just open your radiator cap and watch.... the return is right near the cap. You'll see that it is not steam, but alot of water that flows out of it.
Don't try to re-engineer the cooling system unless you really know what you're doing..... I don't think Chevy would spend the money on those pipes unless they had to.
-Dave C. '97 Z28
All SBC's have had a crossover between the heads that takes the hot water (hot water rises) from the top section of the heads and sends it back to the radiator. The older SBC's had it on the front of the intake manifold and the thermostat would be mounted where it came together. On the LT-1, the thermostat is on the waterpump and the intake manifold is dry, so they still need to get the hot water out of the heads. The "crossover" takes the water from both heads and brings it back to the radiator. Gm decided to route this through the throttle body for heating it up, but if you do the bypass you should connect the hose from one side of the TB to the hose on the other side so the water can still get back to the radiator.
If you want to see how much water actually flows, just open your radiator cap and watch.... the return is right near the cap. You'll see that it is not steam, but alot of water that flows out of it.
Don't try to re-engineer the cooling system unless you really know what you're doing..... I don't think Chevy would spend the money on those pipes unless they had to.
-Dave C. '97 Z28
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Joined: Feb 2004
Posts: 4,800
Re: Deleting the coolant crossover tube??
Originally Posted by 91LT16SpdFormy
My buddy elim his on his 95 Camaro and I elim mine on my LT1 swap and have no probs at all.
Re: Deleting the coolant crossover tube??
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Joined: Dec 1969
Posts: 27,727
From: Little Rock, AR
Re: Deleting the coolant crossover tube??
Originally Posted by zoso1959
what effect will this have if you do throttle body bypass and don't cap off the ends
and if you do cap off the ends?
thanks
zoso
and if you do cap off the ends?
thanks
zoso
