SmokedOutZ28

iTrader: (35)

I'm working with a LS engine with H/C/I setup with 160 T-stat, Stock waterpump. I can leave the car idling and sitting the highest the temp will get is 180 - 190 in any outside temp, as soon as I take it out on the road temps shoot up. I was out on the open highway 75mph 1800 rpms temps went from 180 to 210 in about 20 min, They never got any higher then that but there is no reason for them to even go up that high with 75mph worth of air blowing across the radiator. I bring the car to idle in a parking lot and the temps start to drop back towards 180. What could it be?? Is my waterpump not keeping up with the demand needed to keep it cool? What are signs of air in the system?

-Fans do work low speed is on @ 170 off 160. High speed on @ 180 off at 171

- Lower air deflector is in place

- Stock waterpump (No leaks)

- 160 T-stat

- It's a swapped car so I'm going off the Autometer aftermarket gauge (Tapped into the water pump) and the sending unit monitered by the computer. They are pretty accurate with eachother.

- I removed the AC condenser just to make sure there is nothing but my ram air infront of the radiator (see pic) but I doubt thats the issue there is at least a 4'' gap between it and the radiator I can fit my fist inbetween it.



- Coolant level Ok, No coolant in the oil so I doubt head gaskets

I can let the car sit for literally 10 min and temps will drop back down to the 180 range, as soon as I got back on the highway within 20 min back up to 210. outside temps were mid 80s

One thing I did notice is that the fans turn off with the car above 35mph but that is the case even with the stock tune. I will look more into that as a possible solution but I want that my last resort.

SmokedOutZ28

iTrader: (35)

UPDATE: this morning I did a idle log on the car that would need to bring temps up pretty high. during idle commanding fans off car reached 230 for the test, I turned the fans on again and within 3 min the temps were back down to 185 and as low as 174 and stayed that way the whole time idling for the next 7 min.

I put the car on Ramps and let it idle until 220 degrees there was no air in the system.

LS6427

iTrader: (2)

230 is getting up there, but I've learned from many years on this site that some LSx engines just run hooter than others. Mine is one of those cool running engines, usually never sees 200 unless its a very hot day in city driving. Normally stays around 180 when cruising. These numbers are from a scanner.

I've also learned that most cooling systems aren't healthy, there's always something wrong with most systems. Either very dirty condensors or radiators (exterior dirt) or an airflow issue. Also, removing your condensor will change how the air flows through the radiator, that could be an issue.

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SmokedOutZ28

iTrader: (35)

I purposely took the car up to 230 degrees so I could get my idle airflow numbers at that temp. By turning off the fans (with HPT) it basically took 15 min idling to reach that temp. When I turned the fans back on it took 3 mins for the car to get back to 185 while idling and 7 more mins to get the temps back to 174 where they stayed solid.

The radiator looks clean & clear externally, now internally there could be a problem. I would hope removing the condenser allows for me air which would cool down the temps not slowly raise them at speed.

What thermostat are you running in your car? Temp and brand??

LS6427

iTrader: (2)

My 160* t-stat was installed 8 years ago when I got my 427ci put it, so I don't know what the brand is. But I've had it out many times over the years doing flushes. I know my t-stat housing has a German name on it.

And I really don't know what my tuner did back then as far as fans coming on and off.

Sounds like maybe your temps aren't bad. I have allot of friends with Vettes, their LSx engines run 225-230 allot of the time.

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Old Geezer

iTrader: (3)

The a/c cond should be MUCH closer to the rad than 4"...3/4" is more desirable. 4" creates a turbulent air flow area, and can/will reduce the cfm thru the rad...

SmokedOutZ28

iTrader: (35)

With the A/C condenser in place temps would be 210-220 while cruising and at the track got up to 240 degrees.

I removed the a/c condenser because there is no more A/C. currently the 4'' gap is between the radiator and my ram air box.

My temps aren't bad while idling. It's moving that is where it gets too hot. On my old H/C setup temps would never go above 195 in any type of weather conditions & temps and thats with the A/C condenser in front of the radiator and a stock T-stat. Same WP, Same radiator, Same fans.

Now with a 160 degree T-stat it's well above 200. I would like my temps to be in the 195 area on a 85+ degree day while cruising around. Keep in mind the outside temp was in the high 70's low 80's when it gets into the 90s with humidity my engine temps will probably jump to the 220-230 range.

LS6427

iTrader: (2)

Well, when you are moving, cruising on the hwy, the only thing that is supposed to provide sufficent cooling is the air dam........fans stay off.
So....if you are getting hot.......its an airflow issue. The condensor, radiator and plastic ducting material around that whole set up, along with the puller fans, is designed for the best airflow. Disrupting that in any way can affect the cooling.

On the hwy, cruising, is when any car should run at its coolest.

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SmokedOutZ28

iTrader: (35)

I'm going to swap the radiator and see if that helps. Start eliminating everything one at a time. There due for replacement due to age!

I can't see the ram air causing a issue when I've talked to people with the same setup who don't experience any cooling issues but knowing my luck it will be.

LS6427

iTrader: (2)

I heas you, I know people running around HOT *** South Florida without condensors and they run ok. But a small difference can change the way the air goes through there and any turbulence kills that flow. And if you do reach a speed that causes turbulence, it will only get worse as speed increases.

Make sure you install an LT1 radiator. Not an LS1 radiator. You just have to cap off one extra port. LT1 radiators have 30% more coling area....from what I've heard.

Like mine pictured below. See that extra port. It makes for a great flush drain. It installs 100% exactly like an LS1 radiator and all the ports and coolant level sensor location as the LS1.

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sixvi6-camaro

iTrader: (9)

Problems started after the 160*.. Possibly the 160* t-stat is faulty and not opening properly. I'd try going back to the stock t-stat or trying another 160*. Also raise the fan on/off settings.. those are way to low and your fans will always run. A 160* t-stat will start to open around 160* and won't fully open until until around 175* Hypertech's general guideline is 184F/175F fan 1 and 194F/185F fan 2.

SmokedOutZ28

iTrader: (35)

Yeah I've read that there better, I currently still have the LT1 style radiator in the car. I will definitely get the same style when I get the new one.


They don't run all the time but they do probably more then there share should be. I was not aware of hypertech's settings and that is the thermostat I am using so I will adjust my fans accordingly.

Let me ask you this..... if a thermostat was sticking wouldn't it get hot and keep climbing rather then the car cooling off rapidly at idle or while sitting with the engine off?

joecar

LS6427 said air dam (not ram air)...

i.e. the lip spoiler that goes across under the bottom of the radiator (see LS6427's pic), it scoops air into the radiator, do you have it...?

SmokedOutZ28

iTrader: (35)

I know exactly what he is talking about and yes it's there see post #1. I have a ram air kit that sits 4'' infront of the radiator (chrs1313 ram air kit... see picture) thats what I'm referring to when I say ram air.

LS6427

iTrader: (2)

Hmmmm. I don't know how hard it is to take that kit off.......but I'd be willing to bet if you went back to the stock air intake system....it would run cooler when cruising. I know it works for some people....its just too much of a touchy thing to mess with.

Does that kit change the shroud that houses the fans in any way...or change the shrouds position at all?

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joecar

Ah, I see it in post #1, sorry/thanks.

SmokedOutZ28

iTrader: (35)

No the kit doesnt mess with the shroud, what it does is take the air directed up from the shroud and send it to the intake instead of to the condenser / radiator.

I don't know the width of the kit, but I do know it does not block the entire radiator coils and with the gap the air that does get sent up should be enough to cool the water.

I will try and remove it and see how it does, I also think I'm going to replace the radiator, cap & thermostat to be safe since I can see the factory part code on the radiator it might still be original from 1997


no problem, looking for idea's and experience with the issue.

LS6427

iTrader: (2)

Its definitely altering the way the air goes through that area though.

If I were you, flush a half gallon of "Formula 88" or "Simple Green" through the radiator and entire cooling system. If the radiator isn't leaking, that will clean it like new.

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SmokedOutZ28

iTrader: (35)

Simple green? and that won't hurt it or damage any parts? how would you recommend doing that?

LS6427

iTrader: (2)

Not at all. I've done it multiple times. I use Formula 88, sold at Home Depot. But any good degreaser will work. Simple Green is ok too.

Here's my write up for a cooling system flush.

Best/easiest way to flush and get every drop of old coolant out.

-Cold engine.
-Remove radiator fill cap.
-Remove the t-stat from the housing. Leave the housing attached to the rubber radiator hose, just remove the 2 housing bolts and pull it away from the water to pump to get to the t-stat. (2-3 minute job).
-Put t-stat housing back on. (1 minute) Just put one bolt in, no need to put them both in, there’s no pressure in the system during the flush.
-Take the entire radiator drain valve (petcock) "off" and let it drain, don't just open the valve itself. It'll drain faster with it off and that’s what you want. ((Buy a new petcock valve before starting this flush process, sometimes they break when you remove them all the way just because they're cheap plastic and they get briddle over time, they're like $2.00))
-Take a hose and stick it in the radiator fill cap, running medium to high.
-Start the engine.
-Turn heat on full blast
-Let it run for about 15-20 minutes or until the water is running out the drain CLEAR.
-((If you want to, you can wait till it runs clear, "close" the drain valve, add some degreaser (I use Formula 88) and let it run for 15 minutes, then drain it all again. Then open the drain and put the hose in for about 5 minutes run it all out till its CLEAR. The degreaser will help break up the crap thats stuck DEEP in the BLOCK that sits and swirls and doesn't like to come out.))
-When it runs clear your entire system is clean.
-Remove the overflow reservoir from the car and clean it out real good. (I had to use gasoline to clean mine out because the sludge and grime was so thick inside. The gas broke it all down and then it flushed right out. I filled it about 1/3 up with gasoline and shook the hell out of it real vigorously, the black stuff kept coming out. I did that like 4 separate times with gasoline till no more chunks of black crap came out. Make sure the lines that go to the reservoir are also cleaned out. Or just buy a new piece of 3/8” heater hose and replace that line, 3 feet will do, then cut to fit. My sludge came from my power steering fluid leaking into my coolant system.)
-Put the t-stat back in.
-Put the overflow reservoir back in.
-Put the drain valve back in. Use the new one, what the hell.
-Put half a jug of Dexcool in the radiator. (Or if you live in very cold places, 1 to 1 ½ jugs of Dexcool)
-Fill the rest with water.
you do not need to use distilled water, clean hose water is just fine, just make sure your city water is clean and not total crap quality.

**Bleeding the system of air:
Start it up and let it run, radiator cap OFF, and let it warm up till the t-stat opens. I rapidly squeeze the upper and lower radiator hose like 20 times while its warming up to help move any air bubbles through the system and by the t-stat on the engine side. When the t-stat opens you’ll see the level drop as you squeeze it, its sucking the coolant through the system. You will also see the coolant start to flow in the radiator fill neck, once it starts to flow the level should drop down a lot, immediately top it off with coolant/water. Then the flow will stop when the t-stat closes. Wait one more time for the t-stat to open again and start to flow, if it drops down again top it off again. Do it a 3rd time if you want to make sure. I always massage the upper hose during the whole process to keep any air bubbles moving through. Always works like a charm. Just keep checking your temp gauge until the t-stat opens for the first time to make sure it’s not sitting there overheating from a trapped bubble. May take 10-15 minutes for the t-stat to open the first time.
If you do start to get hot while sitting there and the t-stat will not open…..you have an air bubble on the engine side of the t-stat. Shut the engine off and rapidly squeeze the upper and lower radiator hoses again. Then start the engine again and see if the t-stat will open. Sometimes you just have to work those hoses to move the air through. Even after it seems topped off after a couple cycles…check it the next time you have a cold engine…top off if needed.

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