Cooling issue

[paxton350]

ok granted it 90 degrees out my temp gauge shouldnt shoot up to 250 when im just cruising 80mph in 6th at 2000rpm... the temp gauge just sloooowly rises and rises until i have to shut the car off... Im not sure if my electric waterpump is the culprit here... its brand new havnt even had it in for 2 months, brand new thermostat, new radiator... one of the 2 fans isnt working due to an electrical connection which im fixing tommorow but i dont think that would cause an almost overheat scenerio? how do you check an electric waterpump for efficiency? do you think a faulty tstat could be doing this?

-chris

[esoteric]

Temp rising at freeway speed is usually always a radiator not being cooled or a faulty radiator all together. If you slow down to highway speeds, say 55 does the temp start to come back down? If so its the ariflow and that second fan issue should solve your problem.

[paxton350]

well sorta esoteric... just cruisin around anywhere the temp just slooowly rises but especially on the freeway at higher speeds it jumps way up to 240-250ish... i did notice if i drive slower it does tend to not get as hot but still up there in temp like around 210... does that second coolant fan being inoperable really create this type of scenerio? i do have the slp switch and usually have both on simaltaneously... the radiator is new last season and is fine...

-chris

[Joe 1320]

Could be the water pump,
could be the thermostat,
could be a hose is collapsing thereby restricting flow.

[Injuneer]

Classic symptom of the air dam not being in place.

Cruising in 6th gear - meaning low engine rpm - the electric fan should circulate a lot more water than the stock pump would. Its at very high RPM that the stock pump may outflow the constant speed electric pump.

One fan being out would explain the lack of cooling at low speeds.

Do you have the correct t'stat for the reverse flow LT1 cooling system?

[paxton350]

Yea its new this season also (tstat)... the air dam underneath the car is also missing but ive never had cooling issues like this before in 90 degree weather....one other thing yesterday when i went to check to see if the electric waterpump was working it (the pump) was so hot it was barley touchable (temp was 250 and shut car down)... is it supposed to get that hot (electric pump)? i was thinking for a split second the tstat wasnt working and the pump was just runnning dry but it would have blown a fuse then right?
ill try to pick up an airdam at the junkyard... now the airdam is that flap underneath front bumper? im going to fix that electric fan and check the tstat...

-chris

[Injuneer]

I've got a cooling system that NEVER has had a problem of any sort..... and its pretty much stock except for the Hypertech 160* t'stat and a Griffin 2" radiator. I remember leaving the shop that does all my work, after they did something on the car, and it ran "normally" in the local streets, but the minute I hit the interstate on the way home, the temperature needle started to climb 210*... 220*... 230*.... the faster I went the higher it climbed.

I pulled over and a quick check revealed the simple black plastic air dam was missing. A 15 minute drive back to the shop to locate the air dam and have it installed solved the problem..... back to the same constant 190-195* its always run.

I couldn't believe it either. If you know you have a non-working fan, that plus the missing air dam is an obvious recipe for trouble.

Also interesting is the fact that the shop I use will not even consider using electric water pumps on high performance setups.

[paxton350]

Why do they frown on electric pumps for race applications? Heres the latest from meziere who claims 100,000 mile reliability as well as released hp and strain on the lt1 motor as well as later models....

"The high flow electric water pump for the LS-1 and LS-6 engines is here. Track, dyno, and most importantly, street testing, has proved engines run cooler at low speeds and gain high end horsepower when running Meziere's bolt on LS1/LS6 pump. In addition to the released power, you get to keep all of your factory accessories.

Taking quality to the extreme, the WP319 features a dual bearing belt idler, billet parts throughout, and a “weather-tite” electrical connection. The pump is backed by a two-year warranty. If you own GM’s hottest cars, you need Meziere’s newest, coolest pump. "

[Injuneer]

Meziere may claim 100K mile reliability, but based on the number of posts I've seen reporting low miileage failures, it must be a real crap shoot.

The "high end" HP is increased, because there's no gear driven water pump using the HP to circulate a huge volume of water, and remove the huge heat load from a high HP application. The pump may outflow the stocker at idle and low speeds, but it has nowhere near the same capacity at 6,000-7,000rpm. There was an SAE paper on the LT1's stock circulation system, and it supported this position. Removing inadequate heat when the engine is under extreme load is going to increase component wear, warp aluminum heads, damage bearings, sap HP due to friction, etc.

The shop also avoided block fill for much the same reason.... negative impact on engine cooling. Their record in successfully building 1,000+HP LT1 engines seemed to support their position.