running hot
Thread Starter
7th Gear
Joined: Sep 2012
Posts: 7
Likes: 0
running hot
just purchased a nice little '94 lt1. It only has 28000 miles. I could only find one thing wrong. When you get in traffic on a hot day, it tends to start warming up pretty good. (220-225). I noticed the dual fan system and the debris on the radiator. Only one fan had dirt in front of it. Kind of tells me that maybe the bottom fan is not kicking on. Any one heard of anything like that?
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
The following link will help you understand the LT1 cooling system:
http://www.theherd.com/articles/lt1_cool.html
Your primary fan should activate at 226 deg, and the secondary at 235 deg. If the fans are operating properly, you will see the temp drop immediately.
Debris definitely should be removed. Make sure you have sufficient coolant in the system, and that the fans operate as designed.
http://www.theherd.com/articles/lt1_cool.html
Your primary fan should activate at 226 deg, and the secondary at 235 deg. If the fans are operating properly, you will see the temp drop immediately.
Debris definitely should be removed. Make sure you have sufficient coolant in the system, and that the fans operate as designed.
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Take the fans off and spend some time with a high pressre water hose blasting the fins clean stuff gets lodged in there. Just getting surface stuff out wont cut it. Or pull the rad. hold it up to the light youll see what I mean. Night and day difference
I understand why GM wanted them running that warm but my god its just not necessary and bakes all the rubbers and plastics under the hood.
I understand why GM wanted them running that warm but my god its just not necessary and bakes all the rubbers and plastics under the hood.
Le Mans Master
Joined: Dec 2006
Posts: 5,139
Likes: 482
From: H-Town Texas
To clean out the radiator fins, it is actually better to use compressed air. If you use high pressure water, be sure to cover the front of the engine so as no back spray hits your opti.
Your temps, as has been said, are normal. I'm not sure about the '94, but my '96 primary fan comes on at 228, secondary at 230.
Your temps, as has been said, are normal. I'm not sure about the '94, but my '96 primary fan comes on at 228, secondary at 230.
Heel & Toe
Joined: Feb 2008
Posts: 21
Likes: 0
From: CA
I replaced my radiator a couple of weeks ago, it was leaking. When I removed the old rad there was a ton of dead/ decaying leaves at the bottom of the rad, between the oil cooler and the rad, enough to block maybe 1/4 of the rad. Could be worth checking.
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Probably won't hurt to do a cooling system flush and refill at the same time as the debris cleaning. Use a good coolant and distilled water in a 50-50 mix. Look at the pressure cap to see if the rubber gasket has any indication of wear. Replace if necessary with one of the proper pressure rating.
If the upper and lower radiator hoses are original, it may be a good idea to replace both.
The temps for the LT1 motors are higher in order to help with emissions. My old '92 would see 195-205 temps on the freeway and on hot summer days, 225-230 was common. IIRC, the stock thermostat was a 195 degree unit. Running the A/C automatically turns on the secondary fan.
If the upper and lower radiator hoses are original, it may be a good idea to replace both.
The temps for the LT1 motors are higher in order to help with emissions. My old '92 would see 195-205 temps on the freeway and on hot summer days, 225-230 was common. IIRC, the stock thermostat was a 195 degree unit. Running the A/C automatically turns on the secondary fan.
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Thread Starter
7th Gear
Joined: Sep 2012
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3rd Gear
Joined: Aug 2012
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From: tx
i'm just gonna jump in here with a related question. I have a 95 A/T that was getting hella hot, so, new everything, rad, hoses,180* stat, W/P. put it on the road today and no difference in operating temp, 205/220 at 70 MPH in 98* ambient air temp, 20% humidity. so i start thinking,,,, if my engine temp is that much hotter than my T-Stat, does the stat ever even close? if not it's like running no stat at all, water just circulates non-stop. I turn the A/C on and the lowest temp I get is 200. The faster I go, the hotter the temp gets. ?????
same thing here. i have not done water pump but i found out that the stat was replaced about a month ago. and the first night i drover her it was a nice 70* and it still got 220
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
As said they all run hot like that. 220-23x is not uncommon.
You can put a cooler temp stat in it and progra the fans to come on earlier.
All that heat just cooks the plastics and rubbers under the hood imo. Shortens electronics life, too.
Stat wont close til operating temp goes below the stats opening temp it should always be circulating when open.
You can put a cooler temp stat in it and progra the fans to come on earlier.
All that heat just cooks the plastics and rubbers under the hood imo. Shortens electronics life, too.
Stat wont close til operating temp goes below the stats opening temp it should always be circulating when open.
Melting Slicks
Joined: Dec 2009
Posts: 2,231
Likes: 284
It should not get that hot while going down the road, only at low speeds where the fans are the only thing that is push air. You guys that are running 220* plus while going down the road have a heat transfer problem. Like a missing air dam or a plugged up radiator w/ debris.