Hi Guys, Have a persistent problem with sudden big drops in water temperature readings which I am trying to fathom before getting to do all the tests they you are screaming at me already... From cold, the car warms at a normal rate until the needle is approaching 3/4 FSD and then falls very quickly to 1/4. Then rises to just below 3/4,as before, then falls back to a position a bit higher than the last fall. This sequence repeats with diminishing falls until the temp settles at its normal operating temperature, from which point the temperature behaves as normal. The other clues are in the levels of coolant and air in the system. The coolant from cold is at the correct level in the expansion tank and at the end of the drive, once the engine has cooled, the level in the tank is almost full. When I then bleed the radiator, the volume of air released in total is sufficient to reduce the level in the coolant tank to exactly the same level as at the start. I have read much on the forum and on the interweb about leaking head gaskets but the aforementioned bleeding excercise only seems to indicate that the air in the system at the start is just re-accumulated in the radiator at the end of the drive and so no new air is being introduced. The only thing I am consumed by now is a faulty thermostat, which I will be replacing this weekend as a shot to nothing. However, I just don't see how a thermostat can mis-function to create these symptoms. I read Birdman's postings about coolant systems and thermostats and he describes something that sounds similar with an aftermarket thermostat but the fluctuations I am seeing are more pronounced and only happen for a few cycles before settling down to normal. Anyway, Just though I would offer this up to you guys in case anyone has experienced the same. Kind regards, Steve
I was experiencing something similar after getting my radiator recored and a new thermostat put in. In my case it was a bleeding problem it progressively got better over time as I drove/bled a few times. The winning combination seemed to be a good Italian tune up to get a lot of fluid pumping through the system and bleed immediately. I hope it's nothing more serious in your case! Best of luck! Cheers! Ruben
Hi Ruben, Thanks for the reply....not particularly worried but more curious about what could be causing the problem. My ownership has been peppered with strange and seemingly inexplicable problems and I have now come to accept this as the "joy of ownership" Just on the re-core note......do you recall how much this cost ?. I was thinking of doing this on mine and had a local quote of $1000 Australian $ (approx 700 USD). This seemed to be a bit steep...especially if I am not certain if there is anything actually wrong with it. Wonder if there is a test for the integrity of a radiator ? Cheers, Steve
l paid $650 for my recore in Sydney but this was about 8 years ago.. Mine was leaking though and it was recored using brass from memory. l think you either have too much air in the system or your temperature sender may be intermittently faulty as well. Note this was for a GT4 but l believe they are virtually the same as a 308,but not interchangeable though.
Hi Maurice, Thanks....The cycles of temp fluctuations happen every drive, exactly the same, always returning to normal operation after the cycles have completed. I am hoping this rules out the gauge and the sender.....not discounting anything at this stage though. The dramatic fall of the temperature makes me think that it is cooler water rushing into the engine or the temp sensor being hit by a pocket of air which only clears when the engine temp / pressure builds again. Gonna have to swap out the thermostat to eliminate this as an issue. Not that confident about the replacement I got. The Birdman tutorial on thermostats is excellent and warns of Non OEM replacements are they are not exactly the same spec. I replaced the original factory fitted SAVARA thermostat only last year with an aftermarket one and have since bought another as a spare I tested the aftermarket spare alongside the SAVARA that I kept (hoarder !) and as Birdman foretold they are just not the same in terms of diameter and Flow rates. My decision is not.....do I put the old SAVARA back in (which made the engine run too cool) or put the flimsier aftermarket one in ? The flow capacity is notably less on the aftermarket and maybe this has unmasked a radiator issue ? Anyway, Will report back on the results at the weekend. Cheers, Steve
I don't think your problem is going to be a big deal. Get a stock t-stat (unless Brian recommends another if he see's this) and bleed it correctly. Ted Rutland told me the reason he only sells the relatively expensive stock unit is because of problems with others. I don't know if a better one is out there but I don't think you can go wrong with stock unlike the radiator cap.
There should not be air in the system after you drive it unless it has not been bled properly. Did you also bleed it at the water pump? I would make sure all air is out of the system before focusing on other issues.
Hoping the thermo is the problem here. The aftermarket ones look really cheap and flimsy when compared side my side and despite the fact they claim they are replacements, the after market ones are not exactly the same dimensions. I have the original SAVARA Thermostat which could possibly be the original (could it ?) and it performed reasonably well but the engine ran too cool, only getting 1/4 of FSD when at normal operating temp. Only having one gasket at my disposal, I think the best option to prove the problem is to re-fit the savara. If OK but cool then go find a decent replacement. Cheers, Steve
Hi Richard, did I bleed it at the water pump.....yep and got absolutely nothing but coolant. When I replaced the original Savara thermostat with a replacement from Superformance, the one they supplied did have a bleed hole in it which is supposed to be positioned uppermost. For the life of me, I can't remember if I positioned this correctly and have been wondering ever since if I actually positioned the hole incorrectly and that this is a contributory factor to my current problem. Worth noting that the latest replacement from Superformance does not even have a bleed hole. Savara going back in....bleed hole atop Cheers, Steve
Cooler temps, hoses stiffen-pipes shrink...chased an airleak for a LONG time- same exact symptoms as yours. Tightened every (I thought) clamp, replaced thermostat, replaced water pump- pressure tested- seemed to fix it- as long as it was summer....inevitably when fall (cooler temps) arrived, so did the erratic temp readings.....FINALLY tracked it down to a weak clamp under the plenum on the expansion tank return line. New clamp- been rock steady since- in all temps and seasons
You most likely have an air bubble 1) Purchase the radiator thumb bleed screw from Ricambia 2) Purchase the E-Z bleed screw for the thermostat from unobtanium supply 3) Purchase and carry a 10mm socket 4) Follow the Birdman bleeding instructions
Hi Steve, my recore was about $600 in Northern California. I did it because of tiny leaks in the radiator... They did a really nice job - was done at Dino Motors in San Mateo (the only shop that will ever touch my Ferraris). It sounds like others are confirming my initial suspicions of an air bubble. Best of luck! Ruben
If there is air entering the cooling system it is either because there is a leak or the head gasket is seeping between the combustion chamber and the water jacket. Air should never "re enter" a cooling system once it has been bled. Does anyone believe that when these cars were new owners had to take them into the dealer every few weeks for cooling system bleeding? No properly operating cooling system on any vehicle requires such a thing. The reason that it seems common on these cars is simply due to age of the components involved - hoses, clamps, gaskets, corroded/pitted surfaces where the hoses attach, etc.
Good point about air leaks! If the system is bled, the car is driven, and then there is air in the system there is a leak somewhere. As boatr2001 noted, they can be difficult to locate. Do you know how old the hoses and clamps are? How about the water pump?
There has been quite some mention of loose pipes, connections or fastenings.....can air actually get into the system knowing that it is supposedly pressurized (apart form the scenario of air being forced into the system through a head gasket breach). I would have expected an unsecured joint to just leak ...surely ? Cheers, Steve
As cooling system cools down, air can be pulled though a weak clamped hose, etc- without actually leaking any coolant. Very little heat is required to "reseal" the area upon restart.... no more leaks for me- no more fluctuating temps. I now bleed only when draining/refilling system. Was MY problem anyway, ymmv. Good luck
Did your after market water pump thermostat have a small hole already in it for bleeding like the original or did you drill one in as per the Birdman link below. Understanding the 308 Thermostat Good luck
I have bought replacement hoses for the rad connections and big pipes and will be progressively fitting them. When the car was last in the workshop for service, they replaced the return coolant pipe (from the rad ) to the expansion tank as they said it was perished inside. This being the case then it is highly likely that other water pipes are the same and could even be spit / leaking just enough to draw air in as you suggest. What is unusual here is that, outwardly, the coolant pipe that got replaced , looked absolutely fine so I wonder what he saw in this pipe just by looking at it such that he decided to change it.....was only an oil service and this pipe therefore wouldn't have needed to be removed. The attached pic of the offending pipe shows he was absolutely spot on but how did he know...maybe this was the benefit of a having a service done by a long time Ferrari service guy who could see that this was the original pipe. Maybe these flaking bits of rubber got stuck in the thermostat ?....they will certainly have be accumulated in the rad. Cheers, Steve PS . I keep every last item I replace...which is a lot now....and my ability to show you pictures in some ways justifies this strange hoarding obsession !! PPS. The pipe was cut to show more clearly the degradation inside the pipe. Image Unavailable, Please Login Image Unavailable, Please Login
Hi Sean, No, the replacement Thermostat I got from Superformance has no bleed hole and I will need to drill one (pics are of this latest Thermostat and the original Savara). I replaced the original Savara thermostat about 12 months ago and I am positive that this replacement, also from Superformance, did have a bleed hole (not sure I put the bleed hole at the top though ...doh). Cheers, Steve Image Unavailable, Please Login Image Unavailable, Please Login
Just to conclude this issue.... When I pulled the thermostat I found that it had a rubber plug / foot which had become detached and was left blocking the hole that allows water to circulate around the engine only upon warm up. I have not seen a thermostat like this and obviously didn't pay much attention when I installed it. The plug was nothing more than a rubber cap with a brass disc inside where the cap was pulled over the bottom of the thermostat. The picture shows the cap after I had re-fitted it back into position. At a guess, I would say that the rubber cap got stuck and was pulled off the base of the thermostat when it had retracted. The thermostat also did not have a bleed hole !. I replaced the thermostat with the BEHR offering from Superformance and drilled the required air bleed hole that was missing. In the pics : Leftmost : Original Savara Factory fit Thermostat Middle : First replacement Thermostat with the rubber plug / Cap Rightmost : The currently installed BEHR thermostat Image Unavailable, Please Login Image Unavailable, Please Login
Although the OPs problem is fixed.... thats exactly correct. Constantly having to bleed the system is rather like having a fuse intermittently blow and carrying a bag of fuses around rather than fixing the problem. Its not difficult to find leaks. Pressure testing kits can be bought cheaply and can be used to test for leaks (checking that pressure is maintained) and for finding leaks by pressurizing and using water and detergent brushed onto all joints and look for bubbles. Its best to test an empty system as air will show leaks more than water. The water pump seal will slightly leak air though so a loss of pressure over an hour or so would be expected. A very common cause of leaks on old cars is corrosion of metal pipes where they join rubber hoses. I found at least 10 leaks of this type on a Lotus Esprit recently.
The Tridon tt235-167 thermostat which is 56mm od and 35mm plunger is available here; http://www.oziautoparts.com.au/tridon-thermostat-part-no-tt235-167/ This is the recommended proper dimensions by Birdman. I just ordered one and will report on it when received. It's cheap enough even with shipping from down under. Other temps are also listed but this one is Dave's recommendation for QVs. Sent from my iPhone using Tapatalk
