5.3l overheating problem
4.8 and LS1 engine shots The 4.8 is using the mechanical fan from the 2000 Tahoe.
The LS1 has a Spal 16".
I just bolted both up in the stock location. No special sealing around the radiator.
Does it matter the radiator hose is up so high? Is it being squished when you close the hood?
The LS1 has a Spal 16".
I just bolted both up in the stock location. No special sealing around the radiator.
Does it matter the radiator hose is up so high? Is it being squished when you close the hood?
Thread Starter
Teching In
Joined: Feb 2008
Posts: 33
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From: Pottstown, PA
Ok,
There is no air in the cooling system, checked for that many times and that is not the problem. I really think the problem is not the cooling system at all and may be related to engine performance/ programing. What should I see for Rear wheel hp with this engine? We ran it on a dyno and got around 220 at the tires. The AFR looked high to me, during a full pull on the dyno Lowest numbers we saw were 13.9 and that was only at around 4500 (pulled to 6k) All the rest of the time the numbers were in the mid 14's. Shouldn't those numbers be in the 12's during a full loaded pull?
There is no air in the cooling system, checked for that many times and that is not the problem. I really think the problem is not the cooling system at all and may be related to engine performance/ programing. What should I see for Rear wheel hp with this engine? We ran it on a dyno and got around 220 at the tires. The AFR looked high to me, during a full pull on the dyno Lowest numbers we saw were 13.9 and that was only at around 4500 (pulled to 6k) All the rest of the time the numbers were in the mid 14's. Shouldn't those numbers be in the 12's during a full loaded pull?
Thread Starter
Teching In
Joined: Feb 2008
Posts: 33
Likes: 0
From: Pottstown, PA
Ok,
There is no air in the cooling system, checked for that many times and that is not the problem. I really think the problem is not the cooling system at all and may be related to engine performance/ programing. What should I see for Rear wheel hp with this engine? We ran it on a dyno and got around 220 at the tires. The AFR looked high to me, during a full pull on the dyno Lowest numbers we saw were 13.9 and that was only at around 4500 (pulled to 6k) All the rest of the time the numbers were in the mid 14's. Shouldn't those numbers be in the 12's during a full loaded pull?
There is no air in the cooling system, checked for that many times and that is not the problem. I really think the problem is not the cooling system at all and may be related to engine performance/ programing. What should I see for Rear wheel hp with this engine? We ran it on a dyno and got around 220 at the tires. The AFR looked high to me, during a full pull on the dyno Lowest numbers we saw were 13.9 and that was only at around 4500 (pulled to 6k) All the rest of the time the numbers were in the mid 14's. Shouldn't those numbers be in the 12's during a full loaded pull?
Thread Starter
Teching In
Joined: Feb 2008
Posts: 33
Likes: 0
From: Pottstown, PA
It also seems like it takes a lot of throttle to keep it going 70, and if you come to even the slightest grade you have to get it to kick down out of Od to keep speed. Just seems like it is not making any power when cruising around 1800-2000
That's what I thought. Is that a lean enough condition to cause high engine temp?
It also seems like it takes a lot of throttle to keep it going 70, and if you come to even the slightest grade you have to get it to kick down out of Od to keep speed. Just seems like it is not making any power when cruising around 1800-2000
It also seems like it takes a lot of throttle to keep it going 70, and if you come to even the slightest grade you have to get it to kick down out of Od to keep speed. Just seems like it is not making any power when cruising around 1800-2000
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I may have missed it, but have you monitored fuel pressure, a lean condition in my opinion would make it run hot, I know you can lean a motor enough to melt down the pistons, so I would think it would overheat like in your situation.
thank god you made this post.
Im having the exact same issues with my 5.3L iroc-z. Im going to run through all my checks tommorow morning. check my coolant level, fuel trims, and fuel pressure. Hope i can figure it out and update you!
Sheldon
Im having the exact same issues with my 5.3L iroc-z. Im going to run through all my checks tommorow morning. check my coolant level, fuel trims, and fuel pressure. Hope i can figure it out and update you!
Sheldon
I got that exact car for my graduation present brand new in 89, ragged it out in just a short time and traded it off, boy was I stupid! But it was the quickest IROC in town for a while!
Thread Starter
Teching In
Joined: Feb 2008
Posts: 33
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From: Pottstown, PA
Fuel pressure is 55lbs and holds steady all the time (drove it with the gauge hooked up to monitor it). The computer was sent back to the guy that did the original tune/ modify of the harness and computer. I He said he put the stock tune back in, but I don't really believe him after some of the stuff he has pulled in the past with this project. I will never use or recommend this guy again and am kicking myself for using him as is.
I have a good pc based program coming to monitor/ data log this thing while I drive it, should have it by next week sometime.
Oh, No codes It has never had any codes..
thanks
Dave
I have a good pc based program coming to monitor/ data log this thing while I drive it, should have it by next week sometime.
Oh, No codes It has never had any codes..
thanks
Dave
Thread Starter
Teching In
Joined: Feb 2008
Posts: 33
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From: Pottstown, PA
I put the dyno sheets with AFR shown up in my pictures here:
http://www.flickr.com/photos/29380571@N03/
http://www.flickr.com/photos/29380571@N03/
Last edited by cjdave; Aug 9, 2008 at 08:04 AM.
blown headgasket /s, cracked block? i had one that was doing the exact same thing. mine turned aout to be a cracked block, the crack was halfway down the cylinder, did not show up in a leakdown because of this. i found it by pressurizing the cooling system to 5psi then applying air pressure to the cylinder like a leakdown test and rotating the engine over. if the cooling system pressure starts to rise thats the effected cylinder. just a thought. mine was a pain in the *** too. it wouldnt overheat at all in the city. but the minute you got up to that speed i guess the cylinder pressures overcome the coolant pressure air in cooling systems does some freeaky things. i have ran cars waaay lean and never overheated because of it. heard mild detonation , melted some pistons but never overheated...hmm weird
Thread Starter
Teching In
Joined: Feb 2008
Posts: 33
Likes: 0
From: Pottstown, PA
Thread Starter
Teching In
Joined: Feb 2008
Posts: 33
Likes: 0
From: Pottstown, PA
blown headgasket /s, cracked block? i had one that was doing the exact same thing. mine turned aout to be a cracked block, the crack was halfway down the cylinder, did not show up in a leakdown because of this. i found it by pressurizing the cooling system to 5psi then applying air pressure to the cylinder like a leakdown test and rotating the engine over. if the cooling system pressure starts to rise thats the effected cylinder. just a thought. mine was a pain in the *** too. it wouldnt overheat at all in the city. but the minute you got up to that speed i guess the cylinder pressures overcome the coolant pressure air in cooling systems does some freeaky things. i have ran cars waaay lean and never overheated because of it. heard mild detonation , melted some pistons but never overheated...hmm weird
yeah, i hear ya. the one i was working on was only a year old, he drove it around with air in the cooling system.-an oil change facility sold him a coolant service he didnt even need. must have caused a hot spot on that cylinder