My dad has told me many times that one day I will inairit his 69 400, but it has had one problem in particular, overheating. I have made many suggestions to him all of which he has already done or heard of that doesn't apply. I can narrow it down by saying the thermostat is applied correctly, the rubber pieces are correctly put on behind the water pump, the head gaskets are put on correctly and he has 50/50 mixture. He has also put an amazing aluminum radiator and has a new MSD distributor that we timed, yet I don't know if the, factory I believe, timing is right for it. One thing I heard is that a fan should be x close to a shroud which I don't think it qualifies for, but the car gets really hot (220+ in less than 20min at idle). I would also like to note my dad has tested all of these things and more at least 4-5+ years ago and some problems may have developed from others and such on. He seems to think it may be over bored but I think it may be extreme to want the engine out and any tips/suggestions would help. If any pictures or information is needed just ask, Thanks!
*Mass edit* I just got off the phone with my dad to which we had a long conversation about the car. The fan clutch is a small flex fan which only expands at certain RPM's which is why at idle the car heats up as fast as it does, but is something that has dropped the temp down when driving. About 6 years ago he had the heads rebuilt and changed to low compression instead of the high compression it had before. He seems to think maybe a bearing has been grounded down and is causing a lot of friction inside the block. The car was entered into car shows many times and taken on many long drives, but it ended around 2009-2010 when he got his job in Seattle. It was then that the car sat and had developed heating problems that wasn't normal and led to the car overheating. The car USED to run perfect(considering it ran about 220-230). If the engine is the ultimate problem, why would it take so long to get to that. As well as about 2 weeks ago, before he came to visit, I decided to start it up and when revved, orangy-brown liquid shot out(head gasket problem duh....or was it?) and I decided to wait until he came to start and see for himself. When he started it to get it out of the garage so I could do the idler arm and it did not shoot out. Even to a few days ago to see if at high RPM's it didn't shoot out, only gas because it runs rich(could that significantly raise the temp?)
Welcome aboard, Nick. Not familiar with *69s, but I do not understand your statement regarding the fan shroud. I would definitely want one on there, and in the correct position. The fan blades should be 1/2 inside the shroud and 1/2 out. Also, what fan do you have on the car? Cal
Thanks for the welcome and the reply, as for the fan shroud there is one there and I measured it yesterday, there in a 2in gap between the tip of the blade and the shroud. It is half in/half out but I was told that it may need to be in more or I would just recycle heat under the Hood. It is a 16in fan w/ 6 blades which imo and from another engine specialist may be too small and the.....plates I believe.. behind the water pump may be too small. I can take pics when I get home as I'm off to school. Also I am still learning many things about cars so I apologize for confusing explanations
Ty for the suggestion, I actually read that and it lea me to discovering this website and from that post we had a lot of relatable problems but I am yet to personaly test the temperatures of the radiator myself.
Is the car a 69 Firebird 400? I believe the FB 400's came with a 19/19.5 inch fan. I have one on mine that is stock, but I may be wrong. This is from the AMA specs. https://firstgenfirebird.org/firebird/1969/ama/ama_page3.html#coolingsystem 7 blade 18 dia. Poer-Flex fan on 6 cyl. with A/C. 7 blade 19.5 dia. fan on all V-8 with A/C 5 blade 19 dia. Power-Flex std. on 400 V-8.except std. 4 blade fan used with Ram Air Option.
What is your definition of "overheating"? There are three common definitions, and I'm not fond of either of the first two:
1. The coolant is actually boiling out the rad cap overflow hose. The temperature required to do this varies with system pressure and anti-freeze concentration. If the coolant is actually boiling out the overflow, the engine has probably already suffered some amount of damage.
2. The coolant temperature is at or above some specified temperature. Different people specify different temperatures. Some "hot" light sensors didn't trigger until 260F. Another issue is WHERE the temperature is measured. Sensors next to an exhaust manifold tend to read higher than sensors in the intake manifold coolant crossover. The engine is in imminent danger of damage.
3. The coolant temperature at or near the thermostat is more than 15 degrees above the thermostat rating, at idle or cruise. A thermostat is intended to set a MINIMUM operating temperature, not the maximum temperature. If the coolant temperature measured near the thermostat is more than 15 degrees above the thermostat rating, the theromostat has no control over system temperature. It has "lost control" of the temperature. The closer the system temperature is to the thermostat rating, at idle or cruise, the better. System temperature will increase somewhat for heavy-throttle or high-rpm use, but when the vehicle returns to idle or cruise, the temperature better go right back down to near the thermostat rating.
A 50/50 is for modern AC cars...if your car does not have AC , best cooling of coolant and water is 33 % coolant 67% water...the most efficient cooling mixture...but AC cars use a higher % for lubrication IIRC.
*Clogged/Dirty Radiator not flowing properply *Collapsed hoses * Blow-by finding it way into coolant->Causes foaming->drasticly reduces heat transfer (Do a Pressure Test) Blown head gasket for example. *Divider plate clearanced appropriately *Test thermostate in boiling water *Air pockets? Drill 1/4 hole in thermostate to pass air pockets. *Type of impeller - Cast is always better and not all cast impellers are the same some are deeper then others. *Fan shrowd in place? air dams in place? baffles in place? Fan clearence around fan shrowd *Temp infread gun can be a great troubleshooting tool- compare input temp to output temps of the radiator and look for cool spots or hot spots. Can be used to compare accuracy of gauge/Sender. *faulty gauge - A second gauge check is always a good idea *clutch Flex or Electric - Its tough to beat a good factory 7 blade with HD clutch. *If electric - is your fan a puller or pusher? pusher fans are not good ,they also block radiator *rich or lean carb setting. *Vacumm leaks cuase lean conditions Carb bolted down? Orange intake alignment pieces? *timming issue - Try simply backoff on the timing and see what happens *Over heating at idle or driving - Generally If at idle or very low speed, then it is likely an airflow problem. If at speed, then it is likely a coolant *Retarded cam - Cam not degreed in correctly on ILC. Read about this more then once. *WP pully diameter for trouble shooting *deck height - Piston down in the hole makes for bad quech. *8 realief pistons notorious for ping and heat realated issues. *Clutch fan test See the PDF in Personal->Car stuff. Cold should spin 3 times or more when you shut off the motor. Hot should spin less then 3. *Adjust Clutch fan for max friction PDF in Personal->Car stuff. *downflow radiator in 66-67 GTOs isn't as efficient, *I recently fixed a 455 that ran hot. The main issues with it was the rear seal was the 400 seal, It made the crank so hot the seal surface turned blue. It also had piston rings that had a ton of radial pressure, causing a lot of friction.
When i rebuilt the 400 in my 69fb, i moved the plate inside the waterpump closer to the impellor. A 160 thermostat was added. It runs at 170 - 190 all day in any weather or traffic conditions, std fan, stock shroud.
I might add, i also installed a huge trans cooler and this seemed to of helped as well ??!!
Overheating seems to be a common topic on this site and most suggestions to alieviate the condition are valid. We tend to tell what worked for us from experience.
You say the temp went to 220 at idle, what about on the open road with the engine running at higher rpm?
My experience has been hot idle caused by retarded timing. Just changing the vacuum advance source from stepped to manifold reduced the temperature at idle. A retarded ignition timing will cause the fuel air mixture to burn as it goes out the exhaust valves transferring heat to the block and coolant. Try a higher idle timing, if that doesn't help you can always change it back.
I would also think think the fan tips should be closer to the shroud but not positive on that one, it should be half in and half out though.
It is a 69 400, when I measured the fan to see 16in I was confused as to why my dad might have put it in there but I did take some pics of the fan clutch and I tried to show how far out it as from the shroud
http://imgur.com/a/JwvAY Just so everyone knows I am on my phone most of the time to reply because I am in school so I have to share pictures through a picture hosted website.
Thanks for the detailed info, it's not problem 1 or 2(I'll see where it's connected when I get home) bad as the car never actually boils over, at idle it gets hot but I ever go the distance (nor would my dad let me) to see if it does get to 250. While running close or at 250(too many close calls) the engine ticks and by now, after installing a new MSD, the coil gets too hot and shuts down( my dad called about the coil and was told that was highly likely the case). The ac is there but not hooked up because my dad said, if I remember, it puts more stress on the engine. Also I already have but here's another link for pics of the fan clutch.also forgot to mention the car runs rich and the timing is set to factory...15 and... I wanna say 34(we had looked it up then a few months ago)
While running on a highway or freeway hitting 70 it gets to maybe 230...ish, on the streets it gets to 250- never over, and shuts down(the coil gets too hot). My dad gets into town next week,lives in seattle due to work, and hopefully we can test it on the road. As to the retarded timing, the car runs rich and it may be apart of what i believe to be a big picture because at idle I rev it to see how that impacts the temp rising speed and gas is leaked out of the exhaust in larger amounts to higher the rpm.
If your overheating going down the road at a speed over 30-40 mph you have air flow problems. IMO the fan does little cooling after 30 mph. I would adjust the timing, make sure you have all filler panels installed, and check the water pump to spacer plate for the correct clearance. Here is a link. http://www.wallaceracing.com/water-pump-mods.php Let the car warm up with the radiator cap off, look for little bubbles in the cooling system. If you see a lot of bubbles you more than likely have a head gasket problem. Check your oil to make sure it is not milky looking. You could also have a sticky thermostat. Changing one out to a lower temp will help the cooling system open and close at a lower temp. If you not driving the car in the winter this should not be a problem at all. The fan also looks a little small for the car but seems to be sitting in the shroud in the right location.
