bigfatls6

iTrader: (34)

I have a buddy that just installed an iron block 408 and he has the stock ls1 fbody radiator and fans. His car is not quite over heating but when he drives it for 20 minutes or so it will get up to 214-218 degrees. is this normal or is the stock fbody radiator just not enough for the 408? It has the 160 thermostat and both fans are running. Fans are also set up for the right on off temps for the 160 thermostat also. Are these temps normal when its this hot out side? Its been right at 100 here in texas. Or is he going to have to upgrade radiators? He also has a th350 set up now instead of the 4l60e so it also runs around at a little higher rpm. cruising at about 55 his rpm runs just a little under 3000 rpm. If the car sits and idles it will actually cool down a little that seems kind of wierd to me.

Blk98Vert

iTrader: (2)

Tell him to get a LT1 radiator, twice the thickness of a LS1 radiator

dr_whigham

iTrader: (49)

LOL, yeah. When you hold the two up next to each other the regular LS1 is actually quite embarrassing....

bww3588

iTrader: (49)

Must be a 93-96 radiator. For some reason in 97 they changed to the thinner ls1 style radiator.

groundczero

iTrader: (2)

I would double check the T-stat, fan programming, and radiator filler cap, and that air flow is not being blocked by anything..
I am running a n/a 600hp 408, and a th400 on a stock radiator with no problems in FL, in a 85 fox.

Redbull87

iTrader: (3)

How well was the car burped for coolant during his initial install?Could have an air pocket,but investing in the lt1 rad is a good idea regardless.Are the rear coolant ports blocked off on the heads?

KRAZY K 2000 TA

iTrader: (5)

sometimes they can be quite challenging to get all the air out.

dr_whigham

iTrader: (49)

I've always had good luck having the wife in the driver's seat looking at the temp gauge right after it's started.
As soon as the engine is running I start squeezing the top radiator hose (Deleted the POS PS cooler)
As SOON as the engine is up to temp I tell her to hold it around 2000-2500 for a few minutes.. WATCHING the gauge. Point being, once it's up to temp, I know the thermostat is open, so raising the RPM's will aid in flushing any bubbles out.

Then I go for a spirited drive if the temp gauge is holding steady.

This method hasn't failed me yet.

01ssreda4

iTrader: (96)

Houston in August and your coolant is 215....I'd say you are doing pretty damn good. I would still invest in an LT1 radiator though.

bigfatls6

iTrader: (34)

Yes the ports on the back of the heads are blocked off and cross over lines are installed in the front. I actually have a manual autometer temp gauge tapped in on top of the water pump and tried getting air there and from the front coolant cross over. I thought the same thing about air being trapped in the system. The car will actually cool down while sitting still just idling but when driving or running it hard it heats up. Just installed a new 160 thermostat that didn't help. New radiator cap. Added redline water wetter and still gets up to 218 or so after driving for 20 min or so. It hasn't ever gotten any hotter than that but I haven't driven it that hard yet and no more than about 20 min. It is hot as hell here in Houston though my iat was maxed at 150 the other day. Also I have hp tuners so I set my fans to both be running by 170. I'm bringing the first one on around 150 and the second at 170. Yesterday I drove it for probably 15 min or so and it got up to about 212 and when I parked it and left it idling for a few minutes to open the garage it dropped down to right around 200 while sitting idling so I'm sure it's getting plenty of airflow

01ssreda4

iTrader: (96)

Stock they run 230+ in this heat. Stop worrying, I can't make my point any clearer.

LS6427

iTrader: (2)

Yes....your temps are NOT that bad at all....I'd say pretty good for 100*F in Texas and HIGH cruising RPM's.

But DEFINITELY get an LT1 radiator. I saw a little difference when I got one with my 427ci in HOT *** South Florida.

.

soundengineer

iTrader: (16)

I have no issues with the stock radiator on my iron 408
will be reusing the stock 2001 LS1 camaro radiator on my Mustang Chassis.

the stock radiator will keep up with a 454!
Just make sure its clean, and make sure you change your fan settings to come on earlier than stock and make sure it doesnt turn off above 35mph like the stock settings are(a lot of people miss that)

the coolant blockoffs are a bad idea
add a coolant crossover tube to the rear and tie it together with the front two ports...your engine will thank you
it will allow you to burp all the air out of the engine quickly and you wont develop steam/hot spots at the rear where most people have issues.

dr_whigham

iTrader: (49)

My 2001 stock LS1 radiator cracked on the side (plastic) on the way to work and left me stranded on the side of the road this spring. Not saying the LS1 radiator is bad, but for the cheap price, there is a MUCH better option out there.

imma_stocker

iTrader: (19)

Get an LT1 radiator and call it good. IIRC it holds an extra gallon.

bigfatls6

iTrader: (34)

Ok guys I installed a larger aftermarket 2 row radiator. At idle it does bad ***. I let it idle after filling it back up with coolant/water and it only got up to about 170. I turned the fans off and let the temp get up to 185 then turned the fans back on and it dropped back down to 169 in just a couple of minutes. Took it out for a drive and still got up to almost 220 while cruising. i cna stop at a red light and it will drop back down from 217 to like 212-214 just while im setting at the light. Im sure it has enough radiator now. This one is 2 times as thick as the stock one. i have the fans running all the time also. first fan comes on at 175 and the second comes on at 185.

01ssreda4

iTrader: (96)

I would try an target the temp around 200. I would set the first fan in the 190s. Fans really aren't supposed to run all the time. That's just my .02.