Still overheats. thinking it may be running to lean. 1987 tbi 350. When I was wiring the system up there was in the wiring diagram a hot fuel module with a wire from the fuse box labled idle/gage and a 20 amp fuse. I could not find the wires for this on the engine harnes. the engine is running very crisp. way better than when it was in the blazer. Could this be making it run hot. I got a new radiator a new 6 blade fan new hoses. At idle it gets to about 190 but soon as it gets moving it seems to continue to rise. It has gotted to 220 the I shut it down. It will not cool back down running after it gets hot it just gets hotter it seems. I still do not have a shroud yet but was hoping to get it to at least hold 200 or so under use then ad a shroud.
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TreeClimber
Well-Known Member
A chevy blazer grill is a lot larger than a jeep grill and as such has a lot more surface area in the radiator itself. You'll probably need a shroud and as large of a fan as possible to cool that motor. Also, have you replaced the thermostat? Original EFI motors are designed to run hotter than carb'd motors and I'd guess that the thermostat is hotter operating temp than you'd expect. At least 195 and maybe 210.
There's a thread about AMC's with a lot of good ideas about cooling engines (and why they run hot) right here
http://www.lebelconsultinggroup.com/NW-Wheelers/forum/showthread.php?t=15726
gotta read thru it, but it does have a lot of ideas
There's a thread about AMC's with a lot of good ideas about cooling engines (and why they run hot) right here
http://www.lebelconsultinggroup.com/NW-Wheelers/forum/showthread.php?t=15726
gotta read thru it, but it does have a lot of ideas
TreeClimber
Well-Known Member
My AMC 401 in a YJ has a four row, 24X20 aluminum radiator and a 19 inch fixed 7 blade fan with a shroud. It still gets hot without an auxilary electric pusher fan in front. I even louvered my hood for ventilation. My problem isn't while driving, it's the low engine rpm doesn't spin the fan fast enough to draw enough air thru the radiator to remove the heat that the engine generates. So when I'm cruising the fan pulls fine, and I'm cool, but as soon as I hit the off ramp, engine RPMs drop, and I start heating up. The electric pushes just enough extra air, that it stays where I want it. Where it bothers me, is hill climbing off road. The engine is working hard, but at low RPMs. So I NEED that extra air flow then.
TreeClimber
Well-Known Member
Couple of ideas. How close is the fan to the radiator, since it's a non-stock application?
CrustyJeep
Well-Known Member
I agree with the general tone of this thread; your cooling system is inadequate for whatever reason. IMO, if your cooling system is anywhere near adequate, no combination of out-of-tune-ness should be able to make it overheat. Unfortunately, putting large motors in small packages makes it tough to have a large enough radiator.
Six blade fan? What does that mean? What type of fan is it? I would recommend a good size clutch fan from a Chev truck or large car. Those things move air like no other. Hit the pull-apart.
I have a TBI 350 and a bolt-in three-row copper conversion radiator in the CJ, and it used to get hot until I tossed in a clutch fan. Electrics didn't work, and neither did flex fans. I don't even need a shroud with the clutch, and it doesn't sound like a pissed off bumble bee 737 hybrid unless it gets a little warm, in which case the fan grabs and lets ago again within about 30 seconds.
Six blade fan? What does that mean? What type of fan is it? I would recommend a good size clutch fan from a Chev truck or large car. Those things move air like no other. Hit the pull-apart.
I have a TBI 350 and a bolt-in three-row copper conversion radiator in the CJ, and it used to get hot until I tossed in a clutch fan. Electrics didn't work, and neither did flex fans. I don't even need a shroud with the clutch, and it doesn't sound like a pissed off bumble bee 737 hybrid unless it gets a little warm, in which case the fan grabs and lets ago again within about 30 seconds.
A flex fan. Can not run a clutch fan no room flex fan is 1" from rad now. can not get a electric on the front side no room between rad and grill. I might have toremove the whole front of the truck and redesign it to fit the blazer radiator, I just did not want to. I have cooled a v8 with less radiator before. Thats why this puzzles me.
