Stu Cool

iTrader: (13)

Cross posting this, also put it on the GenIII external engine forum. Who has experience with Evans, Edelbrock or PRW High Flow pumps? How well do they work, have you seen improved cooling? I am having cooling issues on high load situations, like pulling long steep hills. My LS1 is basically stock with a Griffin radiator that should cool 700+ hp. The Griffin folks are suggesting a high flow pump and/or a smaller water pump pulley. My pump and pulley are stock 2000 F-body, so the pulley is not easily changed.

Please share your experience. Thanks

Pat

i r teh noobz

iTrader: (4)

No before and after comparison, but I've been running a "Cat" brand pump purchased from a former vendor on my swap for a few years with no issues at all, even when running a stock Nissan radiator from 1988. They claim a 30% increase in flow over stock.

Is your issue speed related at all? Perhaps your radiator isn't getting enough air.



I took a quick look at your swap journal. Do you happen to have a part number for that air filter setup you used? I'm planning to redo mine and I'd prefer something like that to sticking my K&N out in the bumper where it will get covered in road grime.

Stu Cool

iTrader: (13)

It is more load related, the car starts getting warm on long steep hills. Once over the top it cools back down. The Griffin people say the car should run 190-195 with their radiator in all conditions with the AC on. It consistently runs 15-20 degrees above that and will get up close to 250 on a long uphill, unless I slow down and turn the AC off. It is better now with my Griffin down flow Rad than it was with the cross flow.

Where did you find the Cat brand pump? I did not find one on a web search.

The Air box is from Spectre, Summit sells them also. I used the 5" diameter. Here is a link to their page with the air boxes. http://www.spectreperformance.com/in...air-boxes.html

Pat

bczee

iTrader: (12)

Pat,

Are you sure that your temp gauge and sender are working correctly? Just a thought, maybe double check it with a scanner or a infra gauge.

BC

01cherryreds10

iTrader: (9)

190-195 seems a bit cool for these engines. They like to work pretty hot

i r teh noobz

iTrader: (4)

I got my pump through this guy:

https://ls1tech.com/forums/member.php?u=66899

But he hasn't been active in over a year. I don't have any original packing or whatnot.

My engine sits around 200-208 all the time with a 195 thermostat.

Stu Cool

iTrader: (13)

I will be getting one of those infared temp sensors this week to evaluate. I am OK with it running 205-210 under normal conditions, my real concern is how hot it gets when put under a load. I have a 2001 Silverado with a 5.3 and that temp gauge hardly ever moves, even when pulling a trailer up hills. One of the things that has occurred to me is I am taking my temp reading from the passenger side head. I am told that the area around #6 and #8 cylinders tend to run hotter and that is where the sensor is. These Hi flow pumps are supposed to solve that. When I had the cross flow radiator the motor actually got hot enough to boil over, again on a long hill on a hot day, so I know the engine is getting hot. This radiator is doing much better, but I want to improve it more. One thing that has occurred to me is I have the CFR straight thermostat housing that runs an SBC type thermostat. I am wondering if that may have an impact, is it somehow restricting flow. Thanks for all your input.

Pat

Andy1

Pat,

I'd be inclined to take a second look at the thermostat as well. The SBC thermostat doesn't have a stem and cap on it like the LSx thermostat which leads me to believe that it might be short-ciruiting some of the hot side directly back into the cold side within the water pump. Perhaps you can Jerry-rig a stock LSx neck and thermostat and run a test?

Also, did you cap-off your steam vents?

Andy1

Stu Cool

iTrader: (13)

Andy, My steam vents are plumbed to my water pump now. I just ordered a PRW Water pump. I now have a port on my radiator and will plumb the steam vents to that when I install the new pump. Found one on EBay

http://www.ebay.com/itm/LS1-High-Flo...2aa137&vxp=mtr

I also ordered a CBM Themostat housing to replace the one I have. This one is designed to use the later replaceable LS type thermostat.

http://www.ebay.com/itm/CBM-10613-GM...983173&vxp=mtr

This should show improvement and remove any flow problems. Now I need to decide if I want to go with the standard 186 degree thermostat or a cooler 160 degree.

Pat

99VetteFRC

I have a big no name aluminum rad in my Chevelle that was in it when I got it and did away with steam tube. I have a mechanical guage in the passenger head at #8 cyl and I use an AutoZone LS1 pump. Even under full boost never goes above 195 with stock tstat and housing. I think running the sbc tstat is most likely the problem.

Andy1

Pat,

I'd suggest you swap out the thermostat and housing first. If that doesn't do it, then go ahead with the water pump afterward. If you do both at the same time, you'll never know which of those (if either) fixes the problem. It's a more sound scientific approach (the engineer/racer in me). I'd be inclined to stay with the 185 thermostat, IMO.

Andy1

John McGraw

Stu,

It has been my experience, that a stock waterpump is more than sufficient to meet the cooling needs of a LS engine. It sounds to me like you are just running out of cooling capacity, and moving the water faster through the radiator, will probably do little to nothing. Airflow and radiator size are the two most likely culprits. The fact the it cools down after you crest the hill, pretty much takes a defective T stat out of the equation. Another thought, is that the ignition timing may be running in the retarded mode for some reason, and this can dramatically affect the running temp of the engine. You might want to scan the engine and assure that the timing is running where it should be.
An engine running retarded, will run hot.


Regards, John McGraw

Pop N Wood

iTrader: (1)

I agree with John. I wouldn't be too quick to rule out an air flow issue.

IR readers only read surface temps. I found it pretty hard to get a meaningful estimate of water temp from one.

Harbor Freight sells a cheap temp gauge that actually fits in an LS head. I used that at one point to double check my stock temp gauge plumbed into the block heater plug. I found there can be temp differences, but the block heater temp was always within 10 degrees or so of the passenger side head. If you are reading 250 up there then you are running hot. If you have enough capacity your temps should stay pretty close to the T stat setting.

My guess is the solution will be increased air flow through the radiator.

Stu Cool

iTrader: (13)

Regarding air flow, I can roll slowly through traffic for hours, with the AC on a 95+ day and not go above about 215. Just the single 16" puller fan going. Same way cruising down the highway at 70 or even 75 on level ground. When I come to a steep hill, like a 5 or 6% grade, the temperature will start going up. The longer the hill the higher it goes. Air flow is the same on the hill as on flat ground. If I turn the AC off, and slow down to 55 or so, the temp will stabilize. Your idea on the timing is something worth looking into.

Thanks for the ideas guys

Pat

Pop N Wood

iTrader: (1)

Air flow is the same but the heat load going up hill is greater. The cooling system might be marginal for level cruise and starts falling behind as soon as the load increases.

There are multiple ways to increase capacity. More water flow is definitely one way. A bigger radiator, improved radiator air flow, adding water wetter, installing an oil cooler are all additional ways of doing the same thing. Any one of those things might give you the added margin you need.

On the highway my fan typically doesn't run and my temps stay down around 175 with a 160 degree thermostat. If I get into traffic and have to slow below 50 or so the fan will cycle on and off on low speed to maintain at most 180. I just have a stock GM astro van radiator and a Taurus fan, but the car does have an oversized radiator opening for lots of natural flow.

If the air can't get out of the engine bay it is like putting a piece of cardboard in front of the radiator. Or an AC condenser.

Andy1

A $30 solution is what I'd be inclined to look at first.That SBC thermostat is still suspect in my (aging) mind, at least that's what I think. Notice that the LSx water pump has a passage between the hot and cold sides that if left open will short circuit the hot and cold sides (You'll be sucking hot coolant right back into the motor)). This is tantamount to reducing the efficiency of the entire cooling system (as if the radiator were undersized). Remove the thermostat housing, and you'll notice a hole (passage) from the cold to the hot side. That hole is normally capped by a spring loaded disc at the end of the stem on the LSx thermostat.

Considering timing, capacity, and air flow are all great suggestions, though I'd consider looking there after installing an LSx thermostat and housing, IMHO.

Andy1

Stu Cool

iTrader: (13)

With the new thermostat housing on the way, I picked up a proper LS thermostat today. After studying diagrams I found from Andy1, looking at pictures of water pumps and examining the thermostat I believe the SBC thermostat may have been the problem all along. I sure hope so! There was no provision to force coolant back through the radiator! I am going to change the thermostat and housing first, then I can send the water pump back if I don't need it. I am very excited at the moment and can hardly wait for the new housing to get here, supposed to be next Monday or Tuesday. Thanks for all your diagnostic help, you guys are great!

Pat

John McGraw

Stu,

I somehow missed you comments about the aftermarket neck that used the Smallblock T stat. I think you have found the culprit!


Regards, John McGraw

Stu Cool

iTrader: (13)

Update, installed the CBM thermostat housing and standard 186 degree LS type thermostat. Took it for a 15 mile test drive with AC on. Outside temp was 87 degrees. Engine temperature never even approached 210 and mostly stayed right around 195. It is definitely running cooler. When I warmed the car up after refilling the radiator, I noticed a lot more water moving once the thermostat opened. I won't have a chance to try it on steep hills for a couple days, but I am pleased with the results so far.

So my advice right now is DO NOT use a thermostat housing that uses a small black Chevy thermostat. It's BAD Ju Ju!

Pat

cmac06

iTrader: (16)

If this is only happening on a grade it seems like something maybe obstructing the flow of water when inclined. What style radiator is it? Slap me if that sounds stupid, but sometimes stupid noob advice can lead to some out of the box thinking by the pros here.