Mondial t thermostat

Discussion in 'Technical Q&A' started by lusso64, Dec 5, 2005.

  1. lusso64

    lusso64 Formula 3

    Apr 12, 2004
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    David
    My t is running a little cool except in traffic, when it gets up to 195 and the fans come on, the rest of the time it runs just on the gauge.

    Assuming I have a stuck thermostat, is it possible to get it out and replace it without too much difficulty, or is this a major job.

    Thanks in advance, Dave
     
  2. GTSRacer

    GTSRacer Rookie

    Aug 12, 2004
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    Hampton, VA
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    Olivier F. Raoust
    Is 195 degrees the hottest you've noticed, even in traffic? If so, I wouldn't worry about it. And how cool is cool when running normally?
    As far as replacing the thermostat, it's not complicated but you need to be somewhat of a contorsionist as it's located forward where water intake/outake pipes are - upper part of the engine but right against firewall. Best position is lying across trunk and engine. A nice, soft blanket and good light will help.
     
  3. lusso64

    lusso64 Formula 3

    Apr 12, 2004
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    Yeah - 195 is about the hottest, but when driving on the freeway it barely goes above the first mark (140?). My concern is that it is running too cold. It also takes a LONG time for the heater to start working - the one in the 355 is almost instant.
     
  4. Ken

    Ken F1 World Champ

    Oct 19, 2001
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    Kenneth

    A very worthwhile concern! If your thermostat is stuck open like mine was, the car will never be running the right temperature and that will start to mess up your engine in time. You'll be leaving sooty deposits everywhere. Change the thing out; you likely can use an off the shelf job as long as you can find the right size and temperature (don't quote me on that in case you need some bizarre feature on it). Depending on where yours is in the cooling system, you may or may not need to drain and refill/bleed it. But you may need to change coolant anyway, so it's a good excuse to get it done.

    Ken
     
  5. 512BLU

    512BLU Karting

    Nov 5, 2003
    164
    Spring Texas
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    G F O
    My wife has an 89 T Cab and it does the same thing. You sit in traffic and it will indicate a "normal" reading on the guage, but if you drive at nearly any speed it indicates that it is running too cold.
     
  6. Dr.T348

    Dr.T348 Formula 3

    Jan 8, 2004
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    Richard T.
    My 348 does the same. Even below 140 on highway. I bought a new thermostat last week. Around $130 at dealer. I don't know if any parts reference from another vehicle. I suspect you could find one cheaper. I am going to try to put in this week. Two bolts on top of housing. I'll let you know if any touble.
     
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  8. ernie

    ernie Two Time F1 World Champ
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    Nov 19, 2001
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    The thermostat isn't hard to change. It should take you about 2 hours. Mostly because you have to remove and drain things. The actual changing of the thermostat itself is done in minutes.

    Here is what you do:

    1) Removing the engine cover. Yes all the way off. This will make the job alot easier by giving you better access. Since your Modial is convertable this also will help with the access.

    2) Get the car in the air and drain some of the coolant out of the radiators. You don't need to empty them, just get enough out so that radiator feed tubes are empty. Save the drained coolant.

    Or if you haven't changed your coolant in the last 12 months, this would be a good time to replace it with new stuff. In that case you will want to drain everything.

    2a) You can also attached a tube to the bleed nipples and then let the water out that way, if you don't want to fool with the radiators. You should do this with the radiator cap off. If you have a preasure tester you can hook it up to help get the coolant out faster.

    3) Disconnect and remove the top feed hose. A word of caution, there will still be some coolant in the hose, so it would help if you had some rags read to catch it.

    4) Remove the three nuts holding the outlet pipe onto the top of the water pump.

    5) Remove the outlet

    6) Remove the thermostat from the water pump.

    7) Remove and save the rubber gasket that goes around the old thermostat. You will need it to put around the new thermostat.

    8) Put the rubber gasket around the new thermostat, and then follow the instructions in reverse to reassemble everything.

    9) Refill the cooling system with the saved coolant. Or if you are changing it then refill with a 50/50 mix of distilled water and coolant.

    10) Bleed the air out of the cooling system. You will want to do this with the heater set to the hottest setting and turned on.

    11) Check for leaks

    Happy wrenching :D
     
  9. lusso64

    lusso64 Formula 3

    Apr 12, 2004
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    Ernie - thanks. That is a lot better than having to drop the engine.

    Looks like a project for the weekend. I'll take some pics and report back once all is done.

    Dave
     
  10. No Doubt

    No Doubt Five Time F1 World Champ
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    #9 No Doubt, Dec 6, 2005
    Last edited by a moderator: Sep 7, 2017
  11. Ken

    Ken F1 World Champ

    Oct 19, 2001
    16,078
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    Just out of curiosity, Pep Boys sells thermostats for $5-10. What features does a Ferrari thermostat have that makes you need theirs, or is it just a non-generic size? Mine is 54mm which was a bear to find at 78C but I eventually found it. $5.95.

    Ken
     
  12. ernie

    ernie Two Time F1 World Champ
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    Nothing really. I tried to find one for mine, but as you said it was a bear to find. In the end I had no success finding one, so I forked over the money for a Ferrari thermostat. You really need it to be the correct size because of the rubber gasket. If the gasket doesn't fix exactly, you won't get a propper seal, and then of course leaks. So you really need to have the exact size.
     
  13. 512BLU

    512BLU Karting

    Nov 5, 2003
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    Spring Texas
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    Most likely this car will have a 30K engine out service in January 2006, so I will wait until then for any of this. Is there any advice of other items that should be replaced other than the obvious timing belts, bearings seals, gaskets etc? Usually FOH does everything plus extra, but Mondial T's are rare in these parts and they have not seen one in quite a while.
     
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  15. lusso64

    lusso64 Formula 3

    Apr 12, 2004
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    Engine and box are the same as a 348, so they shouldn't have any problems....
     
  16. lusso64

    lusso64 Formula 3

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    #14 lusso64, Dec 10, 2005
    Last edited by a moderator: Sep 7, 2017
    As threatened, I am now reporting back with what was found and some pics.

    First, access was a lot easier than expected. Ferrari thoughtfully created an access panel behind the seats that opens right in front of the thermostat housing. So, no breaking my back or crawling over the car.

    There is a coolant system drain plug (17MM socket required) under the front right side of the car in the aluminium pipe that attached to the radiator. The coolant plug is just behind the small (1.5 x 1 inch) crossmember, so is a little hard to see when you have your head half under there. It is easily felt however, and access is easy.

    Once the coolant is drained and the access panel removed, removing the thermostat requires remoavl of 3 10mm nylock nuts. One of these also hold the bracket for the accellerator cable. I also removed the small electric module or junction (no idea what it is) that is in friont of the thermostat housing and pushed it to one side. This requires a 6 mm socket.

    The thermostat housing comes off easily and gives satisfactory access to the thermostat for removal. I didn't bother removing the hose from the housing.

    Now for the weird part.... The thermostat was indeed jammed open. It was jammed by the little "plug" thingy that sits in the weep hole. (See attached pic). I have never seen this before. Anyway, I just cut the thing off completely, replaced the thermostat and put everything back together and added all the coolant that I had drained. I then followed the advice of many which is to bleed the system many times, and then twice more for good measure.

    Now the car warms up nice and quickly and the heater blows nice hot air.

    Thanks to all for their advice and information. Total time taken was about 90 minutes (I did have a helper!) and total cost was $0.

    Dave
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  17. No Doubt

    No Doubt Five Time F1 World Champ
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    Nice write up. Thanks for the pictorial follow-up.

    A $0.00 Ferrari engine issue fix...life is good.
     
  18. ernie

    ernie Two Time F1 World Champ
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    Nice work Dave.

    Thanks for the update.
     
  19. j7ols

    j7ols Karting

    Sep 11, 2005
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    Greenville, NC
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    Jools Bourne
    Following on from this thread; my 355 was/is running cool, about 150 Deg F rising appropriately in trafiic and controlled by cooling fans. I convinced myself that the stat was stuck open (as we have here), ordered and new one ($110, don't get me started) and set about replacing.

    Got to the old one and found it closed. Tested it in the house with a thermocouple and it opens and closes about 190 Deg F, just like it says on the tin. New one does exactly the same. I put the new one in as I was already in there.

    So, why does it indicate its running cold? Is the sender a common fail? Surely not the gauge? No oil temp (F1) so I can't see if that is related. I think the sender is close to the stat so before I put it all back together it might be worth changing?

    Anyone know the resistance of the sender at room temp? I could give it a quick check.

    Thanks,

    Jools
     
  20. lusso64

    lusso64 Formula 3

    Apr 12, 2004
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    Jools,

    No idea :) but I do have a 355 at home that I can check tonight for you. Out of interest does your 355 warm up fairly quickly, say within 5 minutes of start up or take a while longer? That would indicate whether the thermostat is doing its job. If it takes too long to warm up then the coolant is circulating via the radiators when cold.

    I'm happy to help out in any way I can - just send me a list of things to measure/check on my car and I can send you the results so you can do a comparision.

    Dave
     
  21. j7ols

    j7ols Karting

    Sep 11, 2005
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    Greenville, NC
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    Jools Bourne
    Dave, thanks for the reply.

    It warms up fairly quickly, which was a hint that the thermostat was working as it should.

    I'd like to know the resistance accross the water temp sender poles. Its located under the expansion tank and is identified in the owners manual. If your tank is off already then its no problem, if its still fitted then don't worry. it would be a major pain just to get this. I will phone around tommorrow and see how much a new one is or if someone can get the info easily. In addition, measuring the resistance at room temp is not really representative of operating temp so to do this properly it should be removed and tested with hot water in one of my wife's best pans.

    Thanks for the offer though.

    I'll post back my findings.

    Jools
     
  22. lusso64

    lusso64 Formula 3

    Apr 12, 2004
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    You're right! It is a pain to get to. Let me know if you have no luck and I'll start dismantling things. I need to detail the engine bay :)

    Good luck with it.
     
  23. benkc

    benkc Rookie

    Jul 3, 2005
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    Tucson
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    Ronald A. Bernstein,
    Excellent tutorial -- I particularly like the pic with your assistant.

    Unfortunately, my Mondial 3.2 is the model before the T so my engine is tranverse -- can't get to thermostat through the rear seat cover.

    Ron
     
  24. smg2

    smg2 F1 Veteran
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    Apr 1, 2004
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    even easier, it sits on the passenger side just below the air box. 15min job.
     
  25. gidge348

    gidge348 Formula Junior

    Dec 12, 2008
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    #23 gidge348, Jan 18, 2009
    Last edited by a moderator: Sep 7, 2017
    Interesting post re pin holding open thermostat, looks like the factory realised this was a problem and added a small fence on later ones.
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