LS1 plumbing - have I done it wrong?
Thread Starter
On The Tree
Joined: May 2004
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From: London, UK
LS1 plumbing - have I done it wrong? I have an LS1 in my Cobra and it's an awesome engine. However, at a recent meet (Le Mans) someone suggested that I had my coolant system plumbed completely wrong.
To summarize:
My heater pipes go straight from the engine to the aftermarket heater matrix, nothing in between. The large coolant pipe from the top of the engine goes to the header/filler tank, which then goes to the top of the radiator. The bottom pipe from the rad. then goes to the large (~2") connection at the water pump. There is a thinner pipe from the top of the engine that goes to the header tank too - I think this is an overflow
He said that his header tank was installed in the heater circuit and that mine might be running cool as a result. I don't really trust the accuracy of my Smiths gauges, but the PCM is stock and only switches the fans on when I've been sitting idling for quite a while - otherwise it just maintains temperature without the fans
Not at home at the moment so can't post pictures, but if someone know what the hell I'm going on about, then please let me know!!
To summarize:
My heater pipes go straight from the engine to the aftermarket heater matrix, nothing in between. The large coolant pipe from the top of the engine goes to the header/filler tank, which then goes to the top of the radiator. The bottom pipe from the rad. then goes to the large (~2") connection at the water pump. There is a thinner pipe from the top of the engine that goes to the header tank too - I think this is an overflow
He said that his header tank was installed in the heater circuit and that mine might be running cool as a result. I don't really trust the accuracy of my Smiths gauges, but the PCM is stock and only switches the fans on when I've been sitting idling for quite a while - otherwise it just maintains temperature without the fans
Not at home at the moment so can't post pictures, but if someone know what the hell I'm going on about, then please let me know!!
It sounds like you have it right. I am assuming that you have a good size aluminum radiator and probably running a 160* thermostat? If this is true it is possible that your cooling system working very efficiently, and if you are running a 160* stat and the computer is not tuned to turn the fans earlier it is still looking for the 200*+ of the stock stat.
Thread Starter
On The Tree
Joined: May 2004
Posts: 161
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From: London, UK
As far as I know, the stat. is stock (it's from a Pontiac Firebird). The radiator isn't ally, it's copper/brass (or whatever normal rads are made from). My mileage isn't as good as I'd expect, about 23mpg (that's British gallons) when I'd expect closer to 27mpg. I'll drop a temperature probe into the system to see what it is actually heating up to
Is the comment about choke a valid one? I'm not getting any smoke from the exhausts, it's just that at low revs, the engine doesn't sound quite silky smooth - has been suggested I change the plugs, although I thought they were supposed to last 100,000 miles. Will also try cleaning the idler motor
Is the comment about choke a valid one? I'm not getting any smoke from the exhausts, it's just that at low revs, the engine doesn't sound quite silky smooth - has been suggested I change the plugs, although I thought they were supposed to last 100,000 miles. Will also try cleaning the idler motor
I don't understand what you mean by "header tank" is this the overflow?
Should be-
-hose on top of water pump to top of radiator
-hose on bottom of water pump to bottom of radiator
-2 hoses on side of water pump to heater core
-small hose from crossover(on the heads)to the top of radiator just below fill cap
Should be-
-hose on top of water pump to top of radiator
-hose on bottom of water pump to bottom of radiator
-2 hoses on side of water pump to heater core
-small hose from crossover(on the heads)to the top of radiator just below fill cap
Last edited by SMAX; Jul 17, 2008 at 08:09 AM.
Ok, it sounds correct. I would check the stat it maybe stuck open. These engines are designed to operate at around 200* so if it is not getting up to temp that could exlpain the less than expected mpg and the rougher idle to off idle characteristics.
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I would just replace it. If it is stuck open probably no major damage can be done to the engine, but if you clean it and it then sticks shut you are looking at overheating which is never good. Cheap insurance
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The expansion tank can be anywhere in the heater or radiator hoses. It just needs to be at the highest point. On the 60s vettes they were in the heater lines because that was the easiest way to get above the level of the heads.
The FE motors on the AC cobras used an expansion tank connected to the thermostat mount forward of the engine.
Gary
The FE motors on the AC cobras used an expansion tank connected to the thermostat mount forward of the engine.
Gary
On The Tree
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From: Stockholm, Sweden
I have Smiths instruments in my Camaro, the tempsender is mounted in the waterpump and it reads between 90 - 100 Centigrades. No matter how I drive or is in traffic jam, it nevers goes above 100. I have set the fans to start at 96 centigrades.
Jan
Jan
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Thread Starter
On The Tree
Joined: May 2004
Posts: 161
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From: London, UK
Christ, Jim, how much was that blue heater hosing? Rest of it looks a bit Dax - considering mine comprises the connector off the back of a toilet as the intake (no word of a lie). How much do GD want for their intake, which is what I presume you've got fitted?
