Tip of the Day: Coolant recovery | FerrariChat

Tip of the Day: Coolant recovery

Discussion in 'Maserati' started by thecarnut, Jul 3, 2017.

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  1. thecarnut

    thecarnut F1 Rookie
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    #1 thecarnut, Jul 3, 2017
    Last edited by a moderator: Sep 7, 2017
    I am getting the Ghibli ready for another 1,500+ mile drive and thought it might benefit someone this simple tip.

    Temporarily replace the windshield washer plastic reservoir with a coolant recovery reservoir. Disconnect the overflow hose that goes from the radiator cap to the floor and instead connect a line from the cap overflow to the coolant reservoir. Now fill the radiator up to the top and the coolant reservoir to the middle. You are done.

    I will be driving in August and it could be hot on some days, plus we will be going up some elevations. This simple modification not only allows for extra fluid in the cooling system but also makes it really easy to check the fluid level.

    The trips ends in Monterrey and I'll remove the coolant reservoir and put back the washer by the time the car goes to Concorso Italiano.

    BTW: on the Bora, where the radiator filling cap is in a really difficult place, I use a coolant reservoir all the time.

    Ivan
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  2. F456M

    F456M F1 Rookie

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    This is great. Should be mandatory on all cars!!
     
  3. rentsch1961

    rentsch1961 Karting

    Oct 22, 2012
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    Alain RENTSCH
    Hi Ivan,
    That's an interesting solution that I would like to use on my Indy.

    How can the coolant be sucked back in the radiator if the expansion tank is on the radiator's cap overflow hose? did you modify the radiator's cap?

    Could you explain the coolant's flow more precisely please?
    Thanks a lot, Alain.
     
  4. thecarnut

    thecarnut F1 Rookie
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    That is a good question ... luckily absolutely no modification is needed as radiator caps are design to "breath" air in and out.

    Let's consider how the cooling system normally works. There is an air gap between the coolant level inside the radiator and the radiator cap. As the coolant warms up it expands and the air pressure inside the radiator goes up. The extra pressure causes the coolant to boil at a higher temperature. In summary, the role of the radiator cap is to increase the coolant boiling temperature by increasing the pressure inside the radiator..

    Most Maserati GT cars were designed to run at .5 bar (7 psi) of pressure. As temperatures increase and the pressure exceeds 7 psi it forces the air inside teh radiator to push against the radiator cap spring and the extra pressure escapes through the overflow. After the engine is off and the coolant starts to cool air has to return into the cooling system, if not the hoses would collapse as there would be a vacuum inside the cooling system. The radiator cap has an extra valve that opens when the outside pressure is higher than the pressure inside the radiator (ie: during the cooling process).

    Installing a coolant recovery system simply replaces air with fluid but everything else works the same.

    Ivan
     
  5. rentsch1961

    rentsch1961 Karting

    Oct 22, 2012
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    Thank you for this clear answer.
    And what about the expansion tank's cap? Just water and air tight?
    A.
     
  6. thecarnut

    thecarnut F1 Rookie
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    The expansion tank is not pressured and cannot be air tight. The cap should have a small hole for the tank to breath. Fluid will enter the expansion tank from the bottom forcing air out of the tank. When the radiator cools the coolant gets sucked back into the radiator and air has to enter the expansion tank.

    Most auto parts store will sell a universal expansion tank. Since on my Ghibli the installation is only temporary, I used plastic ties to hold it in place.

    Ivan
     
  7. rentsch1961

    rentsch1961 Karting

    Oct 22, 2012
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    Alain RENTSCH
    And could you kindly remember us the correct procedure to fill the cooling system et control the coolant level in a car WITHOUT expansion tank?

    Thank you very much for your very useful tips, Alain.
     
  8. staatsof

    staatsof Nine Time F1 World Champ
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    I don't know if your Bora came with the external overflow tank when you got it but at the time when Gary Simeon bought the car he took it over to a friend of mine's house in the SF bay area. All three of us owned Boras at that point. My friend George had problems with spewing coolant while running through the car to redline when he first got his Bora. He made a number of modifications to the car to combat this symptom on of which was to add the coolant recovery tank. I imagine that Gary may have gotten that as a suggestion at the time?

    I have the identical system on my 99 Suburban which now has a bit of exhaust gas being pushed into the coolant. I'm running an open cooling system on that car as it's not worth fixing the head gaskets and the overflow tank handles this problem very nicely! The excess gas escapes WO pushing coolant out of the system whereas with a standard cap pressure it splits open the radiator during sudden exhaust gas injection during wide open throttle up a hill or something.

    I never did put the overflow tank my Bora as I never spewed coolant once the car was sorted properly even in very, very hot weather like 100F. But I think it's probably a terrific idea none the less if only as insurance!
     
  9. thecarnut

    thecarnut F1 Rookie
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    On a front engine car such as the Ghibli, Indy, Mexico ... etc it is quite easy. Fill the radiator with a fixture of coolant and distilled water almost to the top. The first few times you drive the car the radiator will expel coolant until it reaches the proper air gap inside the radiator.

    On a Bora it is a bit tricky as air can trap inside the system. On the thermostat housing there will either be a vent screw or a small hose that will need to be opened to let the system vent while it is being filled. I then raise the back of the car and fill the system.
    The problem with the Bora is that the radiator cap is in a location that is very difficult to reach, plus is hard to check the level. I am convinced that the engineer that came up with the location for the radiator cap also designed the location for the clutch fluid reservoir.

    When servicing the cooling system make sure the manual heater shutoff valve is open and that the heater valve is in the hot position.

    Ivan
     
  10. thecarnut

    thecarnut F1 Rookie
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    #10 thecarnut, Jul 5, 2017
    Last edited by a moderator: Sep 7, 2017
    I forgot to mention something important ..... if installing a coolant recovery system make sure the radiator cap has a rubber seal along the top.

    On a normal system where air is being expelled the top seal is not needed, although it does not hurt to have it. For coolant recovery to work properly the fluid has to go out the overflow nipple and no air can come into the system from the top of the cap.

    Ivan
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  11. thecarnut

    thecarnut F1 Rookie
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    #11 thecarnut, Jul 5, 2017
    Last edited by a moderator: Sep 7, 2017
    There was no recovery reservoir when I got the Bora.

    For those not too familiar with the Bora, the normal filler cap is located inside a compartment in the engine bay. You need a funnel with a flexible hose to get to the darn thing .... and then there is no way of knowing how full it is until it overflows.

    On the Bora I semi-permanently installed the coolant recovery. No holes were drilled nor modifications made, but different from the Ghibli where it is only temporary, on the Bora I use the recovery reservoir all the time as it makes checking fluid level so much easier ... plus it adds at least 1/2 gallon of coolant to the system. I took the overflow hose that normally goes to the floor and connected an "L" adapter to the end; to that the hose that goes to the recovery reservoir .... very easy.

    Ivan
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  12. staatsof

    staatsof Nine Time F1 World Champ
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    Oh OK, my friend George installed one about twice that size behind the upturn in the LH carpet panel. Claus Groth did the same thing to his. It was a nice kit available at the time with a nice basket that held the tank I think?
     
  13. staatsof

    staatsof Nine Time F1 World Champ
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    Lift the rear as far up as possible and it fills/bleeds easier.

    Another big aid in purging air is to add a T tap at the top of the RH side of the radiator where it connects to the line that goes through the A pillar and up over the roof.

    Then put a 2 ft or so length of hose on there permanently with a brass fish tank valve at the end.

    Then you can bleed the air out by pulling that hose and valve out from behind the bumper, opening the valve and dropping it in an elevated container of coolant until all the bubbles are gone.
     
  14. emsiegel13

    emsiegel13 Formula Junior
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    I took the tank in the compartment of the Bora and had a sight window put in so I could judge where the water level is. Now I have to figure out where to put an overflow tank but anything that make for better use of the Bora is worth the trouble.
     

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