The 350 in my 68 LeSabre stays cool above 40mph, but slowly heats up and way up in stop and go. I'm new to the car so I don't know the history. I put in a mechanical temp gauge that I'm reading from. New thermostat, I realized yesterday the vacuum advance wasn't working, replaced that and re-timed (20 adv @ idle on manifold), and today I replaced the radiator with an aluminum core one from radiator.com. None of this has had any effect whatsoever. There is no shroud, and here's a pic of what seems like lots of clearance between the solid fan and the rad. Could this whole thing be because of that? I was hoping to go electric fans, but no one in town had them (even generics that go right on the rad) and I was hoping to get back on the road today. I figure it's either this fan/shroud situation, the water pump, or the engine block is plugged up. I'm open to suggestions. Thanks!
You need a shroud. If it is hot in slow/stop and go, and fine on the highway, that's airflow (typically). And nearly 1" fan to radiator pulls best (with shroud). You want about 50/50 blade in/out of shroud and large enough diameter that you have no more than 1-inch clearance in the circumference, or you get a lot of "stalling" airflow around the outer edge of the shroud/fan area and all those things negate good airflow. What temps are you getting in stop and go? Also, pick up the "infrared" reader guns, and use that to check inlet/outlet, head temps, the intake around the t-stat and on the flat parts of the radiator near the inlet and outlet hoses. That will give you a good idea of overall heat and cooling, since the temp gauges can be off 10 degrees or more, and you are only getting a single point temp reading. My EFI temp reading on both of my cars compared to the mechanical gauges can are off about 15 degrees (gauge reads hotter) , and I have verified with the reader that there is that much difference in the locations of the sender units. Doubt the block is a problem. There may be some scale, but typically a block will have real trouble with blockage if it has sat with only water, left open, and has severe rust/scale problems. A closed system and engine that has been in running condition, the block will not be too bad. If you are not hitting 220-225 in standing or stop and go, keep an eye on things and get a good fan. I use Spal fans (the dual set) and can send you a link for the best price I have found for them. I also recommend "the AutoCoolGuy" fan controllers (PWM). Higher amp fans proved better cooling. Do not spend money on cheaper fans, or you will find you spend a lot more getting that correct.
Get a shroud and a clutch fan on there. They will do a better job if correct than electric fans. What is the specs on the aluminum radiator? One or 2 core? What size are the tubes? That fan, what does it measure tip edge to tip edge? 4 blade?
For that car you want a proper factory mechanical fan, clutch, and shroud. Nothing else will work as well. GM did not build these cars to overheat.
The 68 LeSabre that did not have AC probably came from the factory with a fixed fan like the one it has now . So that is probably correct . A shroud would probably cure the problem .
Ive got a 2 two .75" tube aluminum champion rad. With a clutch fan, shroud, it would hang out at ~200 with a 195 thermostat. Switched to electric fans because the fan and spacer would crack water pumps. I had to use a spacer because the 350 is a lot shorter front to back than the 307 or 305 that could have come in my regal. But for your car a shroud is a must regardless of what type of mechanical fan you have.
yeah plenty of junk trucks around. hell buy me some e fans and send em my way and you can have the one off my 72 and the fan. should work ok with a 68.
Take the valve cover off and look for a build up of gunk over center exhaust ports. Nothing like oil Rather a mix of coolant and oil. In my estimate the 68 engine was good for around 30 thousand miles before the heads went bad. My 68 motor has been running for quite some time although I replaced heads allready.Twice I should say. Now as it runs a steam is present when oil filler cap is removed. Steam continues when engine is shut off- cap open. Tho I have more heads I'm not going to install them. Block needs boring out. I'm your case it depends how long your engine has been running. Might be the cooling system has been compromised. Hope for the best ,but for 68 expect the worst. I will take a pic when things cool down.
Looks like just a 4-blade fan. Might need a fan with more blades (like 7), especially if it has AC.... but it really needs a shroud for the fan to cool properly (and it reduces your chances of ripping your fingers off when you work on it).
Electric fans are the way to go, you will have no regrets if the fan cfm is sized right. Your car could idle all day on the hottest day of the year in stop and go traffic. Josh
Has anyone had to upgrade alternator after switching to cooling fans due to higher amperage? Thanks Frank
20 advanced at idle? That does not sound right. Also sounds like you have air flow issues below 40. Which seems to be the missing fan shroud. Still don’t seem like just a shroud will do that much. again? Explain the 20 advanced at idle? You may want to check your distributor part number to be correct for the year of car.
If the VA is hooked to manifold vacuum, it could easily be 20* timing at idle depending on initial advance.
That car likely left the plant with no shroud as did a lot with no ac and a fixed fan. I would lean towards a timing issue a or a lean condition. What temp is the thermostat and how hot is it getting?
If you don't mind posting a link I'd really appreciate it so I can also dig into this mod. My stock setup is exactly the same as the op's no shroud or fan clutch on my car.
