308 temp issues

Hi. Firstly you need to check your radiator when the car is hot. Make sure that the radiator temp is more or less equal on the top and bottom of both sides. If cooler on one side it may indicate a blockage in which case you would need to remove and re-rod or re-core. Secondly have you bled the cooling system properly.The Ferrari 308 system requires proper bleeding. You need to Google Jonathan Bird. There is a step by step instruction on how to do this. You may want to double check whether your thermostat is working properly. Info to check this is also on JB site. Finally perhaps you should get your fans to come on at a lower temp. I had a similar problem and after many hours of heartache eventually sorted out the problem. I find that from time to time it is necessary to bleed the system and get rid of the air as it tends to creep in over a period. Let me know if this info helps. Mike Dewar ( South Africa)

 

In addition to the above. It may be that you have a faulty gauge or water sender unit. Suggestion is to check the engine temp with an infra red temp gauge. You can check all areas of the engine, radiator and water pipes. This will confirm whether you have a problem or not. If gauge is a problem it is rather expense but you normally find that it is the sender unit which is inexpensive.

 

I installed this on my car:

http://www.summitracing.com/parts/hda-3653

It'a an adjustable temp fan switch. I safety wired the probe to the back of the radiator and set the switch to come on at my preferred temp. No more mysteries about what is going on with the screw-in switch, and a very easy installation to boot.

 

Fans running at full speed?

Both fans running?

Fans running in right direction?

Fuse boxes updated?

Hood foam installed?

Radiator known good?

Radiator bled?

Thermostat known good?

Thermostat housing bled?

Expansion tank without leaks?

Expansion tank cap known good and correct rated pressure?

That would be my initial short list.

 

The adjustable temp switch and the far superior and inexpensive fans (I used a 10" and 12" Hayden) are available at local auto parts stores. Those fans are easily mounted in place of the OEM fans (I used the exhaust pipe mount found in chats about AC) and faired (sealed) to the radiator with aluminum tape, suggest also using the tape around the radiator to help seal and direct air into the radiator and out of the interior. On my '84 308 Euro the radiator temp switch is easily accessed on the bottom right back side of the radiator so you can jumper those wires with an on/off switch (that I made accessible through the louvers so I don't even have to open the front lid) and/or connect the adjustable temp switch. Simply add multiple pronged connectors to the OEM temp switch to add additional (parallel) switches. With the manual switch "on" both fans come on with the ignition switch. Since I live in Florida, I also installed a louvered panel beneath the battery and a new thermostat. I did all this while upgrading to a RetroAir AC and now I have a very cool interior along with a cool engine
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I went threw all of the above, fan switches, thermostat, water pump and finally had the radiator sonically cleaned and now without 30 years of sediment my 308's temp runs normal again.

 

I have a totally stock cooling system and on a hot day (90+) the temp will creep above 195 or maybe just below 200. Once you get moving it will cool to just below 195. I do not see this as a problem as it is within normal operating guidelines.

As others have noted, bleeding the system is critical. There are two points to bleed from.

You may also want to check your expansion tank cap. If it is not holding pressure you will have problems. This seems unlikely but given all the recent talk about this part, I figured I would mention it.

 

+1

My 85 operates exactly the same. 195 seems like a high number but it's actually well within normal operating temp for most engines, Ferrari or otherwise. As long as your fans are kicking in over 195 and you're not headed to the red zone you should be fine. Chalk it up to the quirks of an under-engineered cooling system from an italian manufacturer in the 80's

 

Hey Gang,

I have been using and promoting a Wahler thermostat on my website for a couple years based on the fact that it has the largest flow orifice of all the aftermarket thermostats--closest to the Savara. But I had an on-and-off problem that I couldn't diagnose until this weekend. I blamed it on a gauge for a while but now I know what it is, and based on his description, I'm pretty sure this is what Steve is experiencing too.

A few years ago I did some extensive research trying to find a replacement for the OEM Savara thermostat that was dead in my car. It has a 56mm flange size and it is a bypass type (dual throw) thermostat. I wrote an article about the thermostat search and how it works on the 308 on my website.

Many people have no issues whatsoever with the Wahler (180°) thermostat that I have been using. However, after putting the Wahler in my car, it exhibited a very strange issue. The car would run about 20°-30° too hot for a while, then all the sudden it would drop down to 180° where it belongs and stay there until I shut the car off. The problem was driving me nuts! (I'm an engineer, I can't stand unexplainable issues like this). At first I was thinking it was air in the system, but when I bled, no air came out. (Air will cause gauge craziness!) Then I thought it was a flaky gauge, but the way the gauge works, a bad connection would cause it to read low, not high. To be sure it wasn't something whacked with the gauge, I bought a new sensor for the gauge, calibrated the gauge with known resistance, and doubled-checked its relative accuracy with an IR thermometer. The gauge was not lying! The car would sometimes (not all the time) go way past 180° when I got it warmed up, then just when I was starting to freak out, it would drop down to the correct temperature and stay there until I turned it off. I assumed I had a bad Wahler thermostat, so I ordered another Wahler and it did the same thing. So I decided Wahler sucked and just put a Stant from NAPA in there--and it did the same thing. I finally figured out the other day what is happening. The Wahler and the Stant have 54mm flanges, (not the correct 56mm flange) so they don't necessarily stay centered in the thermostat housing. These thermostats are "close enough" that they fit in the car, but they can wiggle around a little within the rubber seal that retains it because there is 2mm of "slop."

When the car is cold, the bypass plunger is retracted. As the car gets warm, the plunger starts to go down, to seal off the direct return from the engine, so all the coolant will come from the radiator. The plunger has to fit into a shallow cylindrical depression in the bottom of the thermost housing to seal it. The 54mm thermostats have just enough wiggle room that occasionally when the plunger goes down, it's not aligned with the depression in the bottom of the housing and thus will not completely shut off the direct return from the engine. This allows some hot coolant from the engine to sneak around and mix with the coolant coming back from the radiator. So the car runs a little hotter than the thermostat should allow. Not dangerously hot, just annoyingly so.

As you drive down the road, the engine is vibrating, the flowing coolant has turbulence, and eventually the thermostat wiggles around into a position where the plunger can finally snap down into the depression. It then seals the bottom and the temperature settles right down to where it belongs. So basically, you can't get reliable performance from any thermostat that has a 54mm flange. You really need a 56mm flange like the original Savara.

This is easier said than done. The reason everyone uses 54mm replacements is because 56mm flange size is much MUCH rarer. There are precious few out there. Fortunately, the Savara also cross references to the one used in the Fiat X/9 (search for Fiat part number 1430640). Several manufacturers make one that is perfect, though the hole in the middle of many of them are not as large as the Wahler and Savara. (Which is actually probably not an issue at all, turns out).

• The Wahler 4033.82D is absolutely PERFECT, (it's the 56mm version of the one I have been using) but I can't seem to buy one anywhere. It's in their catalog but not available anyplace I can find on-line.

• If you are in Australia/New Zealand, The Tridon TT235 is a perfect thermostat too, by the dimensions, but good luck finding one in the USA.

I have found two that should fit which are readily available in the USA. The Beck/Arnley 1430640 and the MotoRad 235180. They are both specifically made for the Fiat. I ordered both just this morning to compare them. I will get back to you. Both are sold by RockAuto, cheap as dirt. (under $10 each) When I have done some testing, I'll report back and update my website's thermostat article.

Maybe my car is picky, or other people don't notice the temperature gauge position as much as I do. A lot of people have put 54mm thermostats in their cars without issue or without noticing this issue. But I no longer believe any thermostat with a 54mm flange should be put into a 308. Too much slop, not enough precision, doesn't reliably close off the bypass valve on demand. My personal advice would be to stop using them.

I will say that I have also tried several different temperatures. For me the 160° thermostat was too cold. My carb car would not get warm enough on cool days. And carb cars don't run well cold. I have been most happy with the 180° thermostat, and I also swapped out to the 180° fan switch in the radiator that Radioman sells. When the thermostat is working correctly, this combination is absolutely rock solid on my gauge at 180° no matter what the car is doing, no matter what the weather is doing. It's like a modern car.

 

I had the same problem this spring. The cap on the tank had a hair line crack in it. The quick fix was a $6 Stant cap and the problem was solved. I still need to order a stock cap for originality. There was a thread on this subject about six months ago.

 

Great advice and a perfect explanation. Thank you for your insights. Maybe this needs to go in the parts sticky?

 

If the therm works, definitely in the parts sticky.

For the OP - check that both fans are running. My car started running hot, and it was because one of the fans was only running intermittently. Replaced the bad motor, and no problems.

 

Certainly fans can be an issue, but only in stop and go traffic. Issues experienced at highway speeds typically have nothing to do with fans.

If you put a 180° thermostat in the car, you should also put in the 180° fan switch. This is probably review to everyone, but obviously as the car warms up, the thermostat regulates the temperature by slowly opening up and balancing the amount of coolant to/from the radiator with the amount it is recirculating around the engine block. Once the engine gets warm enough that the thermostat is all the way open (and the bypass valve is all the way closed) it is sending all the coolant to the radiator and none is being recirculated locally. At that point, the thermostat has done all it can do to keep your car cool. Now the responsibility falls to the radiator.

At highway speeds, there is plenty of airflow through the radiator to cool the coolant sufficiently to keep the engine at 180° on the hottest day--as long as the radiator is in good shape. However, at stop and go speeds around town, you need those fans. They need to kick on and keep that airflow going. A radiator doesn't work without airflow! So you should always have a 180° fan switch to go with your 180° thermostat.

If your car runs warm around town but not on the highway, you got fan issues. (It could be they aren't both running, could be the wrong temperature on the switch, electrical issues with the car, etc.)

If your car runs warm all the time, you more likely have radiator or thermostat issues.

A properly functioning 308 cooling system with a 180° thermostat and fan switch will never quite hit 195° on the gauge no matter what you do. (Unless of course your gauge is whacked).

One of the problems with the stock system is that it's all based on a 192° thermostat & fan switch. If you think about it, by the time the coolant runs all the way up from the engine to the radiator, then trickles down to the bottom of the radiator where the thermostatic fan switch is, it has cooled somewhat. So for the fans to kick on, that water has to be 192° down at the fan switch. Clearly it has to be well over 210° at the block. If your target is to get the block around 195° (Manufacturer's target and ideal temperature) you need a thermostat and fan switch just a tad cooler than that. Hence, 180° on both. Even if you elect to stick with the 192° stock thermostat, you will be simply amazed at how much cooler the car is in traffic with a 180° fan switch. Everyone should have one of those.

By the way, I use 180° in my car because it's a carb car and it's cranky when its too cold. Radioman has a lot more experience with this than I do and he likes the 160° thermostats in the QV because they seem to generate more heat than the carb cars and are not as sensitive to running too cool. On a hot day, both a 160° and a 180° thermostat will be wide open once the car is warmed up, so there isn't much functional difference. On a cool day, the car with the 160° thermostat will run quite a bit cooler. The carb cars often don't like it.

Birdman

 

Ding ding ding. Exactly. When the thermostat is physically unable to completely close off the bypass valve, the flow to the radiator is reduced. Coolant is getting there, (the radiator will feel hot to the touch) but not as much as it should. The radiator doesn't get as hot and the fan switch isn't getting warm enough to kick the fans on. This symptom is one of the things that helped me diagnose the issue.

 

Okay, I'm back with another update.

I can confirm that the Beck/Arnley 1430640 is 56mm in diameter and looks like it should be a perfect 308 thermostat. The "inner diameter" (diameter of the flow orifice) is about 28 mm versus the OEM 31 mm. I'll have to put it in the car after I get back from vacation and see how it works. The MotoRad 235180, while listed as fitting for the same cross reference, is in fact 54mm flange size, not 56mm. So it is no better than the Wahler.

 

Birdman, the T-stat issue is that most all stats are on/off. The OEM spec unit has an actual temp curve for lift. The WSM covers the temp/lift over time function. Given the volume of the cooling system I'm assuming they did this to avoid temp 'shocking' the sensors on the engine management side and to keep emissions values where required.

 

I had my radiator roses out a few years ago. That plus a new thermostat and a proper bleed when coolant has been changed have kept my car running very cool ever since. No tricky workarounds necessary. Money well spent.

 

+1

 

I recently purchased the Retroair compressor upgrade kit for my 308 QV. As you may know, the installation instructions are not that detailed.

Does anyone know where the 3/8" x 1/2" spacer should be installed?


Any help would be greatly appreciated.

Thanks
Bill

 

Hey all, I just posted in the General Technical Q&A thread but the topic applies to this thread a bit as well...
http://www.ferrarichat.com/forum/technical-q/295793-80-308-radiator-fan-switch.html

The crux of the thread for me:
Just diagnosed that I have a bad thermo-fan switch on my radiator. I'm going to need to replace it but curious how many folks out there have changed to a 180F switch? After some chat searching I see this popping up quite a lot as something folks like to do.

 

This was a "modification" I tried way back in the late 90's. In fact it was probably my first thread here, I believe in about 02 or 03.

I have about 20 years of observation now and I can tell you it didn't make any difference in my case.

 

Thread seems a candidate for necromancy . Though, quite useful in that regard.

 

Since we can't see inside the radiator, most haven't a clue that the tubes are plugged up after 30 or 40 years.

Years ago, I was having some overheating issues with my 328GTS on a hot 90F day. Everything was operating normally, checked coolant level, cap, thermostat, water pump and fans, but it was occasionally spewing coolant, and temps would run on the hot side. I took it to a trusted independent Ferrari specialist and he did the same checks (all okay), and decided to pull the radiator and have it "rodded out" as he called it. He farmed the work to a local radiator specialty shop. They open it, brush or push a wire down all the tubes and pressure wash it thoroughly, then weld it back up and paint it. Once reinstalled, the car never came close to overheating again. He says it is a common problem on the 308/328/Mondials....they get the same clogged arteries like any middle aged person. lol

 

I had my radiator cleaned, re soldered and flow tested. Replaced the brushes on both radiator fan motors. No issues with heat in traffic or with AC.