need help with a 308 overheating problem

WOW all that and it still overheat?

 

Maybe you're running lean?

 

I know you already did a pressure test but these tanks tend to have pin hole leaks ... what about your heater hoses and heater cores? Are the fans blowing fast enough?

 

Probably a pin hole leak where the upper radiator hose connects (from wiggling the hose off and on) That is where mine was.

 

This is a little terrifying... I have an '84 QV (USA) with a slight overheating problem (runs at the three quarter mark of the temp gauge in anything but wide open highway at speed). Took it in this weekend to be checked (still waiting to hear) but, other than checking the coolant, bleeding the radiator once, and making sure the fans come on, I haven't done any of the battery of tests you have. It's disconcerting that someone could do all those tests and still not be able to diagnose the problem.

Good luck with it, I hope you can get it figured out. It's clear you've "done your homework", at least.

J.

 

Two big things.

1. You have to bleed the cooling system at BOTH ends of the car to get all the air out. There is a bleeder on the thermostat housing as well as the radiator.

2. You must be sure that all the foam around the radiator is there. Also, there should be a strip of foam across the underside of the hood to seal against the top of the radiator when the hood is closed. This piece of foam disintegrates quickly and vanishes. Without it, the air goes right over the radiator and the radiator is very inefficient. Go to the local hardware store and get a kit of foam strips for around window AC units, and glue it on with some spray adhesive. You will be amazed how much of a difference it makes.

Birdman

 

Does it over heat at freeway speeds or when idling around town?

 

What is the oil tempature when the water temp. is reading at 225*. Also do we assume you are running 50/50 antifreeze and are you using any water wetter. Also what is your timing set to and is it advancing correctly. Also check the sparkplugs to see how lean the motor is running. Also is the AC condensor blocked and is the foam over the front of the spare tire carrier still there. I don't know where else to go. Oh also get a heat gun and check the input and output of the raditor. You may want to check different places on the block.

 

I agree with Birdman, check the foam

 

THANKS!! Someone pointed out to me this weekend that I had missing foam (which I was aware), but I didn't realize it could affect the heating/cooling so much... This sounds like an easy fix. (Hope it helps the originator of this thread too!)

 

I guess this FOAM missing on my 308 QV explain why Im getting some warm air inside and under the dash. Thanks

 

i've replaced the foam on my 85 gtb.don't think it's made any difference. bled the therm screw with heater valves open and it did drop temp a little (5-10) but still running hot although oil temp needle is at the six oclock position(180). have not taken actual coolant temp though.cabin temps are very uncomfortable. planning rad cap 1.1 and new therm. willl try vw golf therm as per sitcky. i've compared photos of ferrari and vw they look identical. will use 87c. after reading previous thread i think i've noticed some coolant on the rear seam at top of rad. will check hose connection integrity as well. all my problems started with a power flush. am also planning heat shielding material behind spare tire well and dash and forward floor panels. there was a thread a while ago about by passing the heater coil altogether. hate to say it but seems like the thing to do down here is plan your service/ out of commision work for the summer and drive all winter. guess it's hot everywhere.

 

It will not help that much. 308's did this when they were new - even C&D mentioned it in an article back in 1980. When I replaced my foam I could not tell a difference.

You should still put it in, though.

 

50/50 is for Alaska. 60% water will cool much better. And YES on the Water Wetter; that stuff actually works!

Ken

 

NOT LIKELY but here is some other wp info..

I did a lot of research when I replaced my wp ( I wound up with a rebuilt unit from dutchman...) some make a BIG DEAL that the impeller is NOT PLASTIC but some composite..they even say the lighter composite impeller improves cooling and increases HP..they then tell you that porsche uses this type of impeller..and when I did the research there were issues on the porsche / bmw forums that these composite impellers on occassion broke apart sending bits through the system others say nonsense....don't want to hijack the thread and make this a WP thread ..all this was already discussed many times...just thought I would respond to the wp item raised.
let's keep this ( another) 308 overheating thread.

 

It appears you are getting hot air from the front trunk off the radiator. There is a hole for some wiring that needs to be resealed. That's what I did and it took care of my legs getting to warm.

 

2. You must be sure that all the foam around the radiator is there. Also, there should be a strip of foam across the underside of the hood to seal against the top of the radiator when the hood is closed.




Any idea how thick this strip is over the radiator? Wouldn't want to bend my hood upon closing.

 

the piece i used was about 2" thick on both the rad top and spare well. the hood balked at closing at first so i just left it partially closed for a day or so and i compressed itself. no problem since.

 

PAT ORRELL thanks I will check that hole where the harnes goes through and reseal it as well as the foam too.

Mike

 

I'm very suspicious of the recore job.
Again, I'm very suspicious of the recore job.

Is the new core a vertical core like your original?
Did the radiator shop use a core at least as beefy as the original?
Does the new core have the same number of channels as the original?
Are the channels of the new core the same diameter as the original?
Is the new core as thick (deep) as the original?
Did the radiator shop give you back your old core?

The 308 radiator is very beefy, more like found on trucks than on passenger cars. Maybe it's because the water is shipped the length of the car and back that the radiator must be so massive.

Is there a Ferrari garage in your area, so you could go look at an original 308 radiator and compare it to yours? Have you visited the radiator shop and looked at a sample of the core they put in your car? Is it comparable to your original core?

My '76 308 had off and on heating up problems until I had the radiator rodded out (not recored). Now it runs cool even on the hottest of Southern California days in stop and go traffic.

 

Can somebody explain or show exactly where this thermostat air bleed valve is? I'm not entirely sure...

thanks,
Greg

 

If you've got one on your '77 308, it's on top of the thermostat housing -- my '78 had one, but I'm having a vague recollection that early 308 didn't, and it was added later:
Image Unavailable, Please Login

 

Thanks Steve..

I thought that was it.

It's just a bolt, so I wasn't sure if that would serve as a bleed port.

I need to open the heater levers all the way, right? (pushed towards the rear)

Very helpful, thanks..
Greg

PS-I'm looking for a WSM on CDROM, so I can search these things myself!

 

You are correct. My 75 308 GT4 does not have the bleeder. To bleed it, you undo the hose clamp. I think someone at some point mentioned that you could stick a thin rod underneath the hose to help create a channel to bleed the air out, but I found that just loosening the hose was enough. At a certain point, coolant/air will start leaking out, then you tighten it when just coolant leaks out.

Hope this helps.

Dom