308 overheating question

195 - 200 is fine on a hot day. Mine is currently pushing 210-220. This is when it's time to do a bleed, check for leaks, flush, etc. I appear to have a lot of air in my system and think it may be a pinhole in the expansion tank...that was just repaired

 

Sounds within normal range to me...but be sure and bleed the system and consider adding a water wetter agent...

 

Yes between 195 to 220 is ok specially on a hot summer day and in traffic.

Not comfortable but if you turn the heater on to max it will help dissapate some of the heat.

 

Bleed..bleed..bleed.

Oh and what else?..oh yeah..bleed!

 

This could be several things - some good, some bad, some terrible. If the cooling system has been flushed regularly (doubtful, but possible, on a car with only 21K miles on the clock), then you might have some trapped air in the cooling system which needs to be bled out - no big deal at all. There is a great procedure floating around here posted by Verell on doing a thorough radiator bleed. I'd do that first - it may take several tries, so you may have to take your time.

Another possibility, if you can't get all the air out (seems to be seeping back into the system from somewhere....) you have a loose hose or a loose head - a Stant Cooling system pressure tester can easily flush out the loose hose culprit. If your system holds good pressure when cold, but air gets in when the engine is hot, then I'd check the coolant expansion tank for signs of gasoline/oil/combustion gasses in the coolant expansion tank - if you have that, I'd look into a new head gasket or re-torquing the head bolts - not 'bad', per-se, but fixable.

You could check your water pump - does it spin freely, and is its pully properly aligned with the others on the same belt? It could be cavitating your coolant, instead of circulating it efficiently throughout your engine - not difficult to fix at all, but hard to spot. Your thermostat might also need investigating - could be worn-out. So, too could your coolant tank CAP. Its a pressurized system - if the spring/seal is shot, the system won't pressurize to the correct BAR rating.

Two other areas to look into would be rodding-out your radiator (she's 25+ years old?). The other thing I'd think about with a low-mileage car would be excessive oxidation/corrosion inside the block coolant journals (some wiseguy left the car sit for years with too much water/not enough glycol in the engine), or warped cylinder heads, but that is much further down the road, troubleshooting-wise.

 

since I started bleeding my rad. after each drive or once a week b4 a drive and added coolant 50/50 my temp is at 165 and has been there now for two weeks and its been about 78 degree's here in sac,so bleed that system

 

don't forget to check and clean the connectors on the temp sending unit. a little corrosion on the terminals will skew temp readings.

 

Morrie can you be a little more specific. If the gage went to "1 line after the 195" then you would be running around 225* water temp.

"I think it's running hotter than it should. It was a very hot day today. I lost one cylinder bank intermittently when a resistor went bad. Got it running OK again but then in traffic it went over the first line above 195, which I assume is about 200."

So if you are looking at this car make sure that the dealer/seller has bled the system and verify that it is running at 195* in traffic with the AC on. It should not run hoitter then that. If it does make sure that you have this fixed if you consider buying this car. My 2 cents

 

I think the temp issue is actually ok, if it gets pegged at the top or above 220 then you are having problems. If you want it to run cooler, you need to enlarge the amount of tubes in the radiator, and use an upgraded pump... nick Forza has them and I think Rutlands has remanuf... that should help.

If you are loosing a bank intermittantly, I would think that could cause a lean running condition in the non firing side... igniting in the exhaust... causing temps to rise higher... that happend to my qv once and new plug wires and a coil fixed that. Dont play around with a 308 that has an overheating problem... I had one with issues... and had to rebuild the engine... long story.

It is helpfull to know that they should be albe to run at normal temps in the summer in moderate traffic... heavy traffic and jams should be avoided.... in MHO.

I live in Atlanta where it gets hot, humid and traffic jams are our specialty.... I stay away. Running the A/C should have both fans going, but again adds some heat to the mix... I used to turn the heat on and that does reduce the temps, but you will feel the heat inside... lts like a real sauna!

 

Spirot....

You are saying the third mark is about 225 degrees and that's OK when in a hot condition. Mine hasn't bumped the third mark yet and the Oil temp stays pretty much normal [at or slightly above the mid mark when driven hard]. I also switched to a hotter plug. I still think I have air getting into the system considering the amount of foam I get when I bleed the car hot. It can last a few minutes.

 

I never run one even in hondas,Im in Austin tx. I use cardboard to block the radiator like a 250. I keep a newish cap as I think thats where it sucks in the air.I bleed cold every cycle,could be a couple times a day.My euro runs 180 but creeps to 200 in traffic.Sammy cars with the barbell bumpers and diaper exhausts run 20 degrees hotter in my experience.On my old 330 GTCs I rerouted the heater exhausts to the wheel wells,looking at the 308 the htrs are smaller,and much tighter installation but I dont run the plastic cover that covers the brake mc and htr s so I could dump hot htr air into the spare wheel well.Plastic spray can caps work well to cap dash intakes.

 

+1...... Something else to consider....my last Ferrari, an 85 QV ran a bit hot at times, or so I thought. Turns out the gauge indicated about 20 degrees too hot, which was verified by one of the those trick thermometers. The connection on the rear of the gauge could also be problematic.

Good luck.

Andy

 

How quickly does your water temp come up? I took the car out last night and noticed it go to 195 just after the warm up light shut off...say 5 minutes.

 

mines alot slower than that,so 20 minutes but then driving down the road it pegs at 165,when racing it at higher r's about 195 not much more than that later since it was burbed

 

Depending on condition I would not get crazy at 225 - stop and go hot out side, but when on the move you should see the temp recover to 195 ish... then creep up at the next stop. if it stays at 225 no matter what, I would look at the gauge, temp switch and see if its reading wrong. My QV did read a bit higher than what the gauge said... about 10 - 15 F....

If you have air in the system you will see eventually the gauge moving erratically as the air pocket gets to the thermostat.. it will spike then come down... if that is the case you should replace the thermostat, test your catch tank cap, refill and then bleed... air from the top of the thermostat and then at the radiator...it also helps to raise the back of the car when bleeding the radiator...

When you refill the tank, open the bleed screw, and fill till it starts to stream out, then close, put the cap on and bring the car up to temp, shut down, raise the back end, and bleed from thermostat then rad.... that should get your air out. dont worry so much about overfilling the tank... it will purge out and get to the right level.
If after that you still have overheating, I would remove the radiator and have it pressure checked, and or re rodded, or re cored... new core will do wonders. when the radiator is off, check to see if you have a bunch of gunk coming out of the botton tube ( return ) if so you have corrosion in your system and should flush...

 

that how I did it "(

 

My 1984 308QV has pretty good cooling, but on a very hot day in traffic it would heat up to about 210F. i know how to bleed the air, which helps. i added some Redline water wetter, and it dropped the temp by a good 10 degrees. Actually, it runs about 10-15 degrees less while moving (180-185) and keeps the temp at about 200F while stopped. Very cool (bad pun) product.

 

The first thing you must do is verify the accuracy of the reading on the guage with a pyrometer. That is step 1 before anything else.

Not sure why you ran the car at fast idle in a shady area.... it will only make it run hotter than at normal idle.

Change the coolant to a mix of one third anti-freeze and two thirds distilled water. Water transfers heat much better than anti-freeze. You don't need freeze protection at this time of the year. Yes, there are water pump lubricants and so forth in the anti-freezed also. Change the coolant every two years. If you live in Alaska then change the coolant ratio back to 50-50 in winter