need help with a 308 overheating problem

I'm starting to think maybe the powerflush caused the problem. You may need to take out the rad. and see what the antifreeze looks like. Is there any dirt or particiles in it and maybe the flushing pluged the rad. Also I find it strange that your oil temp is running at 195* (6 o'clock) and your water temp is running at 230*+. That doesn't make sense to me. I find that my oil temp tracks my water temp. Both around 175*. Keep searchin and let us know.

 

Rotting out these rads DOES NOT WORK. I have spoken to countless people who rotted out the rad on a 308 only to still run hot. The stock rad works great when it is in good shape. I had mine re-cored and used the original tanks. Make sure you go to a really good rad shop and choose the guy with the most grey hairs. These rads need to be made exact or they will not fit. It takes an experienced hand but is not overly difficult either. My car, regardless of the heat, will not run hot. My recommendation is the following:

1. Re-core the rad
2. Make sure the system is properly bled
3. Make sure the foam is properly installed around the rad
4. Make sure your fuse blocks are good

 

I concur with Nuvolari!
My 308GT4 does not overheat in traffic in 36c+ ambient. And it didn't overheat when I only had 1 working fan. (I was nervous of course but it never overheated). I had the rad recored as part of some mandatory work before even driving the car after purchase.

308's have one or two bleed points. they all have one at top RH side of rad. The one on top of thermostat housing came later. I bleed my system cold, by raising the rear of the car slightly to ensure that the header tank is higher than the radiator vent.
If there are any leaks in the system then you will get air mixed with the antifreeze.

Gerrit

 

I am afraid that I must agree with you on this point. Mine was rodded twice. It helped. In fact, it cured a "overheating" problem but it still runs on the warm side under certain conditions. Not all the time by any means, just if the conditions play out just right. I have to be careful about dodging heavy traffic still just to be on the safe side. Otherwise I see about 3/4 to the right instead of all the way as it did before. I have basically learned to live with it but now I just may go ahead and go the re-core route this winter.

 

Debated having the stock radiator re-cored... but in the end felt it was better to replace the decades old unit with Fchat sponsor Nick Forza's aluminum unit. Even at the track with ambient 90F and running her hard she has never gone over 100C (usually sits at 90 to 95C). In stop and go traffic she stays at most around 85C. Added benefit, oil temps is down to 110C at most.

Last year with stock radiator she would go over 110C... and the oil temps also rose to 125C. Obviously this was not good so made efforts at the end of track season last year to lower engine temps for this seasons track events.

For regular street driving the stuff i did may be overkill, though knowing the system works well at keeping temps at good level is piece of mind. Enhancing the cooling is relatively inexpensive, rebuilding a Ferrari motor is not.

 

Yo Steven,
How much is the Nick Rad?

Birdman

 

$899

http://www.nicksforzaferrari.com/forzaferrariwebsite1_003.htm

 

Whenever I service a 3x8 with the thermostat bleed screw, I drill a hole up the center, & a cross hole down into the center hole to create a true bleed screw. Believe I use a 3/32" drill, but it isn't too critical as long as it leaves reasonable wall thickness.

This eliminates the problem of dropping the screw just as coolant starts bubbling out while you're by yourself(don't ask)...

 

Today I had the pleasure of getting stuck in bumper to bumper traffic for 30 minutes on an 85 degree day. My 75 GT4 never got hot. New aluminum radiator and Hyundai fans (which fit). Fan technology has changed a lot over the years. The new fans significantly raise airflow. My original radiator had so much "stuff" in it that it must have weighed a ton! A worthwhile investment if you drive the ca frequently.

 

It is not unheard-of for 308 water-temp gauges to fail in a way that causes them to read high. Happened to me on a '77 several years ago. Try to check the water temp independently -- I did this by pulling my temp sensor and measuring its resistance in a pan of boiling water so I could compare it to the actual resistance observed during an "overheating" condition.

 

Hi, I've read this (and other) threads on this matter and am asking for more advice... I've got an 84 308 QV that is running really hot (almost at max). I've had a BUNCH of things checked and have eliminated a great deal. Here is what's been done so far:

(1) System was repeatedly bled to get air out.
(2) New radiator cap on expansion tank.
(3) Radiator itself removed and flushed.
(4) Thermostat replaced.
(5) Fans checked (they come on).
(6) Fans swapped with another car's, to make sure they weren't just slow.
(7) Water pump checked (seems to pump fine).
(8) Head gasket test done (clear).
(9) Foam under hood replaced.
(10) No coolant leak, and obviously there's coolant in the car.
(11) Temp gauge checked (it's fine), and engine temp separately measured (it is in fact running hot).

ANYONE HAVE ANY IDEA WHAT THE PROBLEM COULD BE?

Sorry for the all caps and for the new posting, but I really need a solution, quick.

Thanks,
J.

 

Have you looked at the thermal switches on the radiator??

 

Hmm,
Sure sounds like you've covered the entire cooling system!

I assume your check of the fans fans included verifying that they are coming on at the right temp.

This is a stretch, have your A/F ratio checked. Could you be running lean, can lead to temp problems.

 

Steven,

About how long did it take you to get the Forza aluminum unit? I've already lost my car for about 3 summer weekends in a row, and as you can see from this thread we've checked just about everything else... I will call Forza but just wanted to get a sense in case you read this first.
Thanks.
J.

 

Yeah, the guy who does my service is really good. He's spent a lot of time trying to figure this out, and he doesn't cut corners. I will pass on the air/fuel suggestion to him. Thanks Verell.

 

jawad,
Was a flow test done on the radiator when it was removed & flushed? (Usually a radiator shop will do this when flushing the radiator, but figured I better ask.)

Also, is this a new problem with the car, if so when did it start overheating, and what was the history relative to when it started overheating?

 

Verell,

Thanks for the follow up. I believe a flow test was done, but I know my service guy is going to look at it again tomorrow. I think he is also planning to put another radiator in the car and run it, if of course that resolves the problem, we'll know it's the rad (even if we don't know exactly what).

As for the history, it's a bit odd, really. I've owned this car only since March of this year. Unfortunately, it did not come with records, but a very thorough PPI was done. Very soon after I picked the car up, it had an overheating problem. This was traced to the coolant being over-filled and having been blown out by initial driving. This was corrected, and the car ran just fine for 2-3 months. Then all of a sudden it started to get really warm (coinciding with the warm weather, I think). Now the temp is a bit out of hand (although the weather has been very warm, I don't think that's the main cause). My driving habits have not changed, and this car is never tracked -- just weekend driving (often spirited and on twisties, but no track). Also, other than having replaced the oil cooler, no other work/changes or after market mods have been done to the car.

Does that give you any other ideas?

Thanks again,
J.

 

Hmm,
Another long shot, you replaced the oil cooler. A 308 gets a fair amount of cooling from hit's oil cooler. Any chance of a flow problem w/the new cooler?

Back to the overfill. That normally doesn't cause overheating. The colant expansion will cause the excess coolant to flow out of the tank & onto the ground. Once the excess is expelled you're at the proper level & the overflow stops.

Is that all that was done, or was some other change made?

Umm, if the coolant level in the tank is too low, you can get air into the system & it'll overheat.

Also, that reminds me of something that came up a few years ago. if I remember correctly , the pickup tube has a 90 degree bend inside the coolant tank. This ensures the open end will suck coolant from down near the bottom of the tank

However, I seem to remember reports of the tube breaking off, or leaking, resulting in aiir getting sucked in & overheating. Try searching the Tech Q&A archives, & the Old Fchat Archives for various combinations of:
coolant tank tube broken

 

Wouldn't that show up on a radiator pressure test?

 

J, I talked to Steve Arena who is working on your car yesterday, he is a factory trained Ferrari tech & an actual customer of mine, so we do know each other, we discussed your cars situation for some time yesterday after you called me, I am waiting to hear back from him on a few items I asked him to check, I think we should be able to sort out the problem shortly, I wish there was more history on your car.

I will have a radiator on stand by if you need one, he is going to pull some plugs, I want to know how the combustion chamber is buning on both cylinder banks as he mentioned to me that the car feels slower than it should. My gut feels says its your cam/ignition timing causing the engine to run hot.

 

Nick,

Thanks so much for your time on the phone with me and with Steve. Steve called me back earlier tonight and you were both right. The cam timing was apparently off! Steve adjusted it and said the car was running MUCH better already! We're putting in a new set of larger fans, together with the timing adjustments, this should solve the problem entirely. If not, your radiator's going in next.

Again, thanks for your help and your follow up on this. You and Steve are both stand up guys and I will recommend both your services/products any chance I get.

Cheers,
J.

 

I had the radiator re-cored with a copper core so I could still use the original Ferrari tanks. After all I have done the coolant still comes out of the tank.
the thermo, water pump, temp guage and sender are brand new. The OE fans were checked and are coming on at 180 degrees and have the correct amps according to specs. I checking into two 12 inch fans to move more ait to the radiator. After this I am at a loss for what else to check. The foam is new and the system has been bled so there is no air at all. After driving, I leave the car running and put a high speed fan in front of the radiator and I ca watchthe temp guage go down to 180. Replacing the OE fans is the only part that has not been done to the cooling system. Any help would be greatly appreciated.
Pat

 

Please excuse my spelling, must be frustration............ Pat

 

Hi Pat
It is a frustrating experience. One thing you didn't list is checking that the fans are rotating in the correct direction. When the fans are on, both should be pushig air at the rad, not out hte front. Easily mixed up by reversing the wires.
(I messed up the spelling so you wouldn't feel too bad

Gerrit
http://dino308gt4.com

 

Yes I have checked the fans and they are pushing air into the radiator. It appears that the fans could be bigger and with more cfms to cool the radiator.
Pat