Damn!! (308 Overheating Post #5,674)

You have never checked the thermostat?......

 

Yeah I'll second that, change the thermostate. Also, when you bleed it make sure you do it with the heater setting turned all the way to hot. That way you do run the chance of air getting in from the heater core. One more thing have you checked the condition of your radiator cap? You may need to get a new one.

 

If it's OK when moving but overheats in traffic it could be that the fans aren't kicking in when they should be (or at all)

 

Hey good point!

 

PenP,
I 2nd checking the fans, Both should be blowing if It's trying to overheat.

The thermoswitch connection at the bottom of the radiator is known for getting corroded. Altho, I'd think that changing the rad would have delt with corrosion. Next is the thermor switch itself being bad.

I understand your frustration tho...

 

Isn't there a relay that controls the thermoswitch?? Worth checking that as well.

 

After you get through checking the fans to make sure they are running, feel how hot the air is coming out the louvers in the snout of your car. If your water pump is putting out sufficient flow at idle, you should notice only a small temperature difference between the driver's side and passenger's side in the blast of air. In my 328, the hot coolant enters at the top on driver's side and flows across and down. If the flow from the water pump is low, little makes it all the way across the cavity at the top of the radiator. Thus the air rushing by the small trickle of coolant falling down the passenger side can easily remove the heat meaning that the passenger's side air blast is a lot less hot than the driver's side if your water pump is not putting out sufficient flow at idle.

While this has not happened on my 328, I have another car that would like to get too hot when running at low rpm and slow speed under load. It's problem was that the clearances between the impeller and cavity it resides in had gotten too large due to corrosion and would not pump sufficient coolant at low rpm. A new water pump immediately fixed the problem.

 

Having the same problems with my 308... I'm sure you've done the searches already, given the humorous title you gave to your posting, but here's a recent thread... http://www.ferrarichat.com/forum/showthread.php?t=113933

If you scroll down you'll see everything I did already (oh and though it says the foam was replaced, it hasn't been yet, that was my mistake). At the end of the day, water pump was checked (seems ok), cam timing was adjusted, new fans went in, the radiator got flushed, new radiator cap, and thermostat replaced, but still overheating badly in traffic...

Not sure what else is left other than the foam but very much doubt that's going to fix it. Really annoying...

 

Check the thermal switch on top of the LH radiator mine went bad with the same symtoms.

 

What I've done with my car is bypassed the thermoswitch for the fans. I made a jumper that connects both of the spade lugs, and heat shrunk the entire connection.So the fans are on all the time. My car is a summer car, and I know that both fans are running all the time to maximize my capacity. In my situation, warmup times are no greater with this approach. Instead of waiting for the fans to kick on at 160 or 180 or whatever switch you have installed, the fans are going once the switch is turned on. What this also does for me, is when I turn the switch on, I hear both fans running, thus I know they will be running when they are needed. My 2 cents.

 

There are test kits for combustion products in coolant. Try commercial auto parts houses. Unlikely that consumer places like PepBoys, & AutoZone will have them. Altho, AZ does occasionally surprise me.

At least that will eliminate , or confirm :{, that possibility.

 

short of incorrect system pressure or a bad t-stat. what about your A/F ratio, is it lean causing a hot runing engine? some times the overheating is becouse the engine is not in tune and running hotter than it should, no fault of the cooling system.
my 2 cents

 

I replaced the cap on mine and it seems to be running cooler. It wasn't over heating as much as it was running 10-deg or so hotter than normal.

The old cap looked brand new too boot.

One thing to know is the OEM cap is 1.1bar which is 15-16lbs, not 7lbs like a lot of them are replaced with (and which is what my old one was).

My car runs ~195 in 95+ heat and high humidity with the AC on to boot. Even if you just replaced it, try a different one. It’s a cheap fix ($6.50 at O’Reilly). I’ll post the PN when I get home for those who care.

 

Sorry to hear of your troubles, I only wish I lived around the corner I would have a look for you.
I would still go for the thermostat, in fact I would have gone for that after the first flush. Radiators and water pump internals take many years to block up, its a very slow process but thermostats just give up. They stick closed open or half way. The half way looks like what could be your problem, going along at speed the water pump is pushing it through the small hole. But when ticking over in traffic it is not circulating fast enough, thus getting hot!

Hope you fix it, keep us posted.

Mark...

 

Is the car boiling over? My 308 gauge has always read a little high. It used to bother me unitl I pulled out my laser temp gun. The gauge is just wrong. 195 on my car reads 205 on the gauge.

Joe

 

You may want to check this out. I updated it today.

http://www.ferrarichat.com/forum/showthread.php?t=76238&highlight=308+cooling

 

no disrespect, BUT THIS IS A BAD BAD BAD IDEA!!

the cooling fans are DESINGED to kick on and off, and they draw a bunch of amps. by leaving them on all the time, the electrical system is not allowed to "rest" and go through a load / charge cycle. my old lambo had the fans "straight wired" and it did nothing but cuase burned up alternators and overgeated connections. the switch is there for a reason and there is NO REASON to wire it to run all the time.

 

Here's a thought . . . the intake manifold water passages on my old motor were all corroded/blocked with calcium near the end holes of the head . . . most of the water was being forced through the middle "elbow connection" hole only . . . . that engine seemed to run hotter than my new motor, but new motor also has new thermostat so???



Sean


P.S. Getting the intake manifold off was a PAIN because of the corrosion!!!

 

Here's a pic of what that looks like - very not pretty. I would pull the manifolds and at least check for this if you are having overheating problems that can't be solved by the 'easier' fixes.
Image Unavailable, Please Login

 

Yep, that's what mine looked like.

Sean

 

My latest Esprit project has that too. I was amazed at how hot the fuses get.

Fortunately, the fuse box is by my knee in that car. For the time being, I'm manually controlling the fans by inserting fuses (3, one for each fan) as necessary. It's suprising how little the fans actually have to run.

 

i really need more sleep so i can spell properly....

i agree, it seems the fans cool better in a cycle and by operating in a cycle, it gives the charging system a way to keep up!