Good observation. In the factory they pressurize the system -cold- in order to do the bleeding operation faster. So, yes, they bleed the system but quicker than us. We need to warm the engine to pressurize the system, and we have to perform it several times because we don't have enough pressure. For sure they have a pressure machine and a recirculating closed liquid system that they connect to the radiador and to the expansion tank -with the thermostat bleeding screw opened-. With these gadgets they can complete the bleeding in a few minutes. The 308/328 cooling system is tricky.
No pressure required. People are really making it far harder than required. All you need to do is open both bleeders, fill until the rad bleeder spits out water and close it. Continue filling until it spits out the thermostat bleeder and close it. By then the tank will probably be more than half full so just cap it off and you are done. I have been doing it day in and day out since the carbed 308 was still in production and we never did any more than that. If you fill it and bleed it hot there is simply no way to get it filled properly because the water has already expanded. Quit making a mountain out of a mole hill.
I agree with the bleeder screw cure, I did this on my GT4 , it was erratic, you open the bleeder screw and you will be surpised the air that escapes.It helps to jack up the rear of the car I think.
I did machine a bleeder screw with a hose barb on the end. I drilled a hole straight thru the new bleeder screw. I slid a hose over this barb. I ran this hose into a container to keep the mess to a minimum. We use the same process with all Subarus in our service centers. Fire off the motor,open the bleeder screw and let the system build up pressure with the internal motor temp. Once the pressure starts buidling it will push the air thru the system and out the bleeder screw/hose into the container. I would not suggest opening both bleeders. You need to work the air bubble thru the system and opening both bleeders will not generate enough cooling system pressure to push the air thru the system and out the bleeder. We bled my cooling system in 20 mins. no air, no over heating. I have checked the system several times asnd still no air. I have now installed a pop off valve in the cooling system. I found an earlier thread to add this to the cooling system. I machined another bleeder screw with a hose barb that is flow thru and always open. I mounted the pressure relief valve over by the heater core on the right side of the car. I ran a hose from the bleeder to the pressure relief valve. What takes place here is a constant relief of any air pressure build up in the cooling system. Howard Musolf 1981 Ferrari 308gtsi. Maserati Spyder.
Bleed the system 3 times now - no more bubbles. Car is now running at approximately 200 degress. I believe I will change the water pump to insure corrct circulation. I thank everyone for their kind advice.
Why would you need to bleed a system multiple times to get the air out? I totally agree with RifleDr...when I had the coolant replaced we drained the coolant. We opened the bleeds, then added coolant unitl it bled out of the radiator bleed; closed that bleed. Then we added fluid till it bled out of the T-Stat housing bleed. Closed that bleed. Then filled system to recommended level. That was all there was too it and car has another 600 miles since then. I don't understand all this multiple bleed stuff - where do these big air bubbles hide? And if they can hide from the first bleed, why didn't they stay hidden? If the system truly must be bled multiple times, it would indicate to me that there is some sort of air leak or a more serious problem, like a blown head gasket between the combustion chamber and the water jacket, etc.
Total waste of time. All the factory ever did was pour water in them. I do it the same way and have done it a thousand times over a few decades now but you just can't help some people.
If my gauge had a red line (like the generic gauge pictured below) where would the red line be? Image Unavailable, Please Login
I had an overheat problem at low speed in my 308 QV. Checked fans and they seemed OK. The problem continued. Pulled a fan motor out and found they are made by LUCAS " Prince of Darkness"!!! They were working intermititly. Replaced them with after market modern shrouded spiral blade fans, problem solved. My 328 has the more modern style fans from the factory.
See page 60 in your 307/84 OM -- max permitted coolant temperature is 230~240 deg F, but, for normal street driving, I'd say that the "yellow" ("you need to be looking into why this bad/not typical condition is happening") zone should start at ~210 deg like that generic gauge implies.
On a nice spring day about 75 degrees outside after 45 minutes of leisurely driving with the A/C off my infrared temperature sensor is reading 205 degrees at the top of the radiator and my temperature gauge seems to indicate about the same. That is in the "acceptable" range but seems a bit hot for the conditions in a car with a 180 degree thermostat. I think I have literally done everything possible to make sure the cooling system is operating correctly and this is the result. What I have done: Replaced ALL the coolant hoses Nicks Forsa Water Pump and a new belt New thermostat Re-cored the radiator (they said that the new core was better than original) New modern fans for the radiator New thermoswitch 50/50 Ethelyn glycol/Water I think the car should run between 180 and 195 at all times. Is that unrealistic? What am I missing?
To begin with a high capacity water pump will do nothing to improve an already marginal system. Its weak link was not an undersized pump and speeding up the water flow will not help. Sorry to say but your car is normal. The 84 and 85 QV was known to be very marginal. 200 or higher was considered normal at lower speeds. It should drop at speed. That is why the 328 got a complete cooling system redesign. And note the 328, 288 and F40 have the same water pump as a 1976 308 in terms of capacity. A bigger pump is just not needed.
I'm curious about how these handheld infared temp guns account for different surface emissivities -- if you measure the temps of parts 8 and 51 do they make sense relative to the temperature you measure at the top of the radiator (i.e., are parts 8 and 51 maybe a little hotter than the top of the radiator)? Image Unavailable, Please Login
The size of the radiator is an issue and the air ingress and egress is a big issue. The 308QV had a grill in the hood to let air out. On the 328 they made it much bigger, tilted the rad so it could be made much bigger and moved the AC condensor out from in front of it. A 328 with a standard waterpump will idle all day with the A/C running in a traffic jam in downtown Riyadh and not get up a sweat.
This is a great point, Steve. I have one of the "high end" RayTech IR guns, with a very narrow field of view. Despite its claimed accuracy, the owners manual specifically discusses the importance of changing the "emissivity" factor, depending on the reflectivity of the surface you're measuring. In that the thermo housings and radiator are of different "colors", the "emissivity" factor of the IR gun really should be adjusted accordingly to yield accurate results. I find that more accurate results can be obtained using my Fluke DVM, with direct contact or even immersion type probes. David
Having owned both of these cars, back to back, Brain's point is right on the money...I never had any issues, or even concerns with my 328 sitting in traffic, whereas my 308 QV always made me a bit nervous as the gauge climbed. David
OK but I don't want a 328 I really prefer the looks of a 308 so what can I do? I realize that the 328 is better in several ways but I want to be able to drive my 308 in the summer without worrying all the time. Steve: I will attempt to make those measurements next time I get a chance. Rifledriver : I agree with what you are saying I have also considered a "Euro" spoiler because they seem to have a bigger area to allow air in. I guess my question to you is if I brought it in to you and said "Fix this problem" what would you recommend?
Thanks very much -- I realize that it is just extra work for you that really doesn't help your situation. David's (higher cost?) IR gun seems to have a user settable emissivity factor -- if yours is a cheaper one, it just might have a note in the OM saying something like "result assumes measuring a matte black surface" or something like that (which for a painted radiator is about right), or maybe some fudge factors to apply to the result for different surface types, so you might check for that if you've got the documentation. If your temp does run a little lower with the coachwork in motion as Brian described, seems like you're "as stock". I know it would only be a psycological improvement, but after all the effort and expense that you've already gone thru, maybe a fresh thermister (item 35) would read half a needle width less
Amen! It's almost unfortunate that the non-contact ones have such great repeatability and resolution. Must be something in human nature that just makes it hard to not equate those properties also to good accuracy -- I know I have that problem
When those cars were still under warranty it was a real issue. Ferrari paid dealers in hot climates a lot of money trying to get the temps down. They finally threw up their hands and adopted a policy that defined overheating as "Boiling over". If it did not boil over it was not a problem in their eyes. What to do about it depends on how far you want to go. Modifying the hood, moving or doing away with the A/C condensor and installing a larger radiator will fix it. As a more practical measure I would go to a large aluminum radiator and use a water/WaterWetter mix and some better, ducted fans.
Following up on what Rifledriver said I called the place that sells the aluminum radiators (Nicks Forza) and talked to the guy there he said that another thing that can help bring down engine temperatures is a modern ignition system. I am paraphrasing here but he basically said that it would bring the temperature down by 20 degrees. Can anyone here confirm or deny that statement? He also sells an aluminum radiator which he claims has something like 50% more cooling capacity. I'm not sure how that translates to my temperature gauge but it sounds good. He stopped short of recommending either item because obviously he can't diagnose the car over the phone. Rifledriver can you clarify/explain what you mean by a "ducted fans?" Here are the fans I currently have: Image Unavailable, Please Login
Today I used a Infared Temp Gun on the car. The in car gauge was reading 200 degrees but the temp at the radiator intake was 150 degrees and 160 degree at the engine. I now suspect the gauge or the sending unit. Comments??
I don't think you are being specific enough about what you are taking the temperature of. What are you taking the temperature of when you say "160 degree at the engine" There are many surfaces in the engine compartment with a wide variety of temperatures.
I used to have the traditional overheat in traffic problem. No more...gauge rarely indicates above 190 now in 90 ambient and stopped in traffic. My cures: 1) Radiator was rodded out. 2) Replaced the decaying foam around the radiator and foam glued under the bonnet. I haven't seen this mentioned in this thread but believe me improper air flow is a MAJOR contributor to overheat - without proper foam - much of the air flows around the radiator instead of through it. BTDT...noted a major big time difference on this one.
