[JoePapa]

Yes - I mean the car

I can't seem to be lucky enough to get rid of the engine driven fan. Here's what I've got:

'69 Firebird 400
Heads have been milled but don't recall amounts
Block decked to zero (not sure if that matters here)

Radiator is Ron Davis 2 1" row. The overall dimensions is the same as the factory 4-row radiator that I had in there.

I've replaced the water pump with the Milodon High flow unit (cast impeller) and clearanced it to the backing plate.

With the engine driven fan, it heats up at idle - takes a while but gets to 210 without fail. The temp drops once I get moving.

I've swapped out thermostats - just prolongs the inevitable.
I've ran straight water and water with water wetter - no dice
Current mix is water, water wetter, and just a little anti-freeze.

The shroud is in place, close, not 100% sealed but pretty close to it. The fan is 1/2 in/out.

This engine showed signs of over heating previously as the engine builder mentioned this to me during the rebuild. Could this just be a bad block?

This week I'll be installing an engine oil temp sender.

Next attempt would probably be to move the oil filter - it's right above the headers and I'm wondering if the headers are heating up the oil which then causes the motor to get hotter then normal. I'm looking for a remote oil filter kit with a built in thermostat; if you have a good supplier, please let me know.

I've tried electric fans - both the Ron Davis shrouded models and the flex a lite ones that are rated at 2950 cfm - 16" puller and 12" pusher. These electric fans cannot cool the motor and in all honesty, the engine driven fan has a hard time.

I'd really like to go back to the electric fans and put that horsepower to the tires. This is my goal.

What have I missed?


Thanks in advance!

[JoePapa]

Yes - I mean the car

I can't seem to be lucky enough to get rid of the engine driven fan. Here's what I've got:

'69 Firebird 400
Heads have been milled but don't recall amounts
Block decked to zero (not sure if that matters here)

Radiator is Ron Davis 2 1" row. The overall dimensions is the same as the factory 4-row radiator that I had in there.

I've replaced the water pump with the Milodon High flow unit (cast impeller) and clearanced it to the backing plate.

With the engine driven fan, it heats up at idle - takes a while but gets to 210 without fail. The temp drops once I get moving.

I've swapped out thermostats - just prolongs the inevitable.
I've ran straight water and water with water wetter - no dice
Current mix is water, water wetter, and just a little anti-freeze.

The shroud is in place, close, not 100% sealed but pretty close to it. The fan is 1/2 in/out.

This engine showed signs of over heating previously as the engine builder mentioned this to me during the rebuild. Could this just be a bad block?

This week I'll be installing an engine oil temp sender.

Next attempt would probably be to move the oil filter - it's right above the headers and I'm wondering if the headers are heating up the oil which then causes the motor to get hotter then normal. I'm looking for a remote oil filter kit with a built in thermostat; if you have a good supplier, please let me know.

I've tried electric fans - both the Ron Davis shrouded models and the flex a lite ones that are rated at 2950 cfm - 16" puller and 12" pusher. These electric fans cannot cool the motor and in all honesty, the engine driven fan has a hard time.

I'd really like to go back to the electric fans and put that horsepower to the tires. This is my goal.

What have I missed?


Thanks in advance!

[Rugratman]

I would suggest your timing may be off.
Also the carb jetting may have the car running a little lean.
Is the fan big enough?

[JoePapa]

The current fan is an 18" flex fan.

The timing is 10 or 12 degrees BTDC at idle, I'll have to double check that to be sure but I believe this is accurate.

I'm feel like it's lean at idle but don't have an 02 sensor (yet). However, with my 825 Mighty Demon it feels a little rich yet still have this same symptom. I've pulled plugs and unless I'm reading them wrong, they confirm this is correct too.

[buwalda]

You probably need a smaller pump pulley. That will increase water flow & fan speed. This website has more info:
www.stewartcomponents.com
They also make an electric booster pump that goes in the bottom radiator hose, but this would be a last resort.

[JoePapa]

Thanks Geoff - another friend said the same thing just this am. I'll check that out - thanks a million!

Joe

[GotGTO?]

Hey Joe,excuse me for asking but did you ever live in Northbrook Illinois?Timber Trails,Lawrence Lane?

[JoePapa]

No, never. Alb. NM and now Austin TX.

[Lil SCAPEGOAT]

Joe:
You did not say why the eng. needed rbld.......Overheating?
How old is the radiator?... Cap?...Sender?...
Guage?...
Does the liquid actually blow over?
sealed system w/ overflow bottle?
Drain some fluid, Look down into radiator w/ light,are Passage tubes clear?

[Lil SCAPEGOAT]

My GTO was running warm @ 89' ambient,then above 92' outside,then temp skyrocketed to 210-220 OW!!
once I ran my hand over top of Rad.,about 1/4 inch above it Pass.side half was cooler,I touched it(not smart),Pass. side top of radiator was cold!!!
Driver side was HOTTTTT!!!!
Time for a New One,I Now have Autometer Guages Too!!
SOME aftermarket hoses are made as "trim to fit"
IF your top hose is too long,the begining of curve area around Altnator Rises UP,Because the end,(@ therm. Hsg.)needs to be trimmed.
IF any part of this hose is higher than the Outlet you are gonna have air trapped in there!!! Waterflow becomes a trickle to get passed the air bubble.WHHEEEEW!!!!
OH! mine ? it only warms up to 170 @ 80' outside, 185-190 @ 100+ outside driving @ 70-80 MPH.!! Flush your system,
Check timing, read spark plugs,use elect. fans!

[bfrazee]

I don't know if you've already seen this, but take a look. Somebody directed me to it, as I also have an overheating problem (350), and I think they've got the answer.

http://forums.performanceyears.com/g...11&m=958104692

[mscicluna007]

You Guys are amazing

I'm running a 1971 400 in a 79 Transam in Australia

Hott was not the word.
The engine is 0.60 oversize
Edelbrock Performer 72cc Heads
9.5 compression
Cruising speed temperatutres were ideal
But less than five mins at idle and the temperature was on 220
as nervous as i was i managed to find a nice backstreet and a coupke of mins driving and the engine was back to 160
There was a problem and i couldn,t put my finger on it. I tried a 160 Thermostat to no avail.
Then going thru a local parts magazine i saw a second hand high flow water pump.
it had dawned here is my problem so i called and was unfortunate as it was sold.
as i was about to hang up i decided to ask if he;d had overheating problems and explained my situation. He refered me to this website and explained the problem.
so i searched thru the stories here and the next day the pump was out
Almost a quarter of an inch
The plate was bent to your recomended clearance and the pump re istalled in just over an hour.
Fired up and drove for ten mins. temperature went to 150 and when returned home was put in the garage and left to idle for 5 mins. temperature was at 180 max.
This modifaction is definately worth the effort.
Thank you for some valuable advice.

[nightwrencher]

also check for exhaust in the cooling system. this usually only causes higher speed issues though. but if the engine was overheated as the builder said, could be cracked, but you think he would have seen that. it could be a crack or head gasket leak, those don't always cause exhaust smoke. NAPA has the coolant testing kit for like $55, woth the investment.

[JoePapa]

Thanks for the replies guys.

Lil SCAPEGOAT - I'll try triming the upper hose. I recently flushed the system about 3-4 times and added a gallon of a temperature reducing additive. This helped but didn't resolve the problem. I did notice the upper hose angle and pushed it down several times to flush out any possible air. Additionally, the front end of the car was up in the air on a jack and the top of the radiator sits taller then the intake. I also added anti-freeze.

69FbirdPhx - I did review that thread and there was a gap. I closed the gap up and even bought a replacement high flow mechanical pump. Still didn't fix the problem for idle.

Dave - it cleaned up very well. He was refering to the valves mostly. The block was decked and the heads were milled and it all squared up beautifully and checked out clean. That question was mostly referring to internal passages.


The problem is at idle, not when I'm moving. The radiator is fairly new (about 5-6 years old) so I haven't tried to get it redone - it's clean inside and has dual 1" rows. I think I should have opted for the dual 1.25" rows instead.

However... now that it's cooler out it runs fine. Maybe I just need to move to some place that doesn't get about 90 degrees in the summer? I'll figure it out eventually and will post the result when I find it - I'm more stubborn then the car


Joe Papa

[buwalda]

Joe,
I have seen cases where an engine has sat for years & developed sediment in the cooling system. One engine I had was full of small, hard pieces of rusted block material, a little smaller than a grain of rice. No matter how many flushes I did, I could never completely get rid of this stuff. After only a few hours of driving, it would block many of the tube openings in the radiator & the engine would run hot. I then had to get the radiator rodded out. I ended up fitting a gauze filter in the top radiator hose to catch this stuff. I had to clean it out every couple of months & eventually I got rid of the stuff. I mention this because you said the radiator is 5-6 years old; it could be partially blocked.

[mscicluna007]

Is their a chance that this is fuel related.
I am still having the same hot temperatures as earlier and my performance shop is telling me to richen the mixtures.
Apparently when it is too lean the cylinder walls heat up.
Their is an interesting article in Pontiac Tech Special Summer 2000 Edition pg.70-72 which details the use of different fuels today and this being a contributing factor to the temperature rising on the vehicles. they suggest an aluminium radiator for the quick fix but i do not feel this well solve everyones problem.
I am going to try running an edelbrock performer with a holley 750 to see if their is a differance.
Also i have heard of performance shops running automationg transmission fluid with the fuel for lubricant. Apparently it does the same job as lead. has anyone heard of this.

Michael

[tininjun67]

I've never heard of running trans fluid with the gas, how much are you supposed to add per gallon? I'd think it would smoke with trans fluid in the gas.

[runningbwdog]

Hi,
Instead of auto trans fluid in you gas, try Marvel Mystery Oil. In airplanes we add about 1/2 pint to the fuel. The mixture lubricates the lower part of the valve stems when it passes through ports in the head above the valves.
It definitely reduces sticking valves.
Mike

[mscicluna007]

only a small amount. supposed to be about 100mm to a tank.

[78 GHOST]

My bet would be on the lack of airflow at idle.

What kind of fan are you using? If it's a stock thermostatically controlled fan clutch, you need to ensure it's working OK. Hayden produces clutches and has a good troubleshooting page on their home page.