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328 Cooling System Leak

Discussion in 'Technical Q&A' started by RussF, Aug 28, 2005.

  1. RussF

    RussF Karting

    Nov 1, 2003
    222
    Washington
    There appears to be a leak in my cooling system but I cannot trace it the source. Here is what I know:

    1. When the level in the holding tank gets low it seems that air gets into the system and prompts a drip a second from just foreward of the passenger rear wheel.

    2. The temperature cycles to about 195 when the thermostat opens, fall back and then the temperature rises and the thermostat opens again, temperature drops and the cycle starts over.

    3. This evening when it happend I pulled over and bled the air out of the radiator. There was a lot of air in it.

    4. After the air bleed the temperature stabilized below 195 and the TS opening/closing stopped.

    5. When I got home there was no leakage although over a week or so I will have to top up the overlow tank.

    6. My conclusion is that air gets into the radiator, heats up and put more pressure on the coolant causing the drip referred to in 1 above. If enought air gets into the rediator I will get a flood of water coming out. This prompted me to change the water pump a month or so ago when I now believe that I did not have to. See earlier thread on this.

    Appreciate any thoughts on this.
     
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  3. 285ferrari

    285ferrari F1 World Champ
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    Probably not related--BUT you never know.--I had the coolant pipe the goes from the water neck down along the right side of the motor crack--the gas tank strap actually rubbed a small hole in it. Enough so that under pressure(car running ) it was fine. No pressure it leaked like crazy in the same place as you describe. Only way to see if it is that is to put it on a lift and reach up there to feel around it.
     
  4. GrigioGuy

    GrigioGuy Splenda Daddy
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    Nov 26, 2001
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    You can also see that area if you take out the passenger rear wheel well liner. If the leak is directly in front of the wheel on that side, it's probably it. Water can take a strange course in bouncing around, so check your hoses too.

    Mine suffered a mystery coolant loss for a while, turned out to be a failing water pump. Check the weepholes to see if they are damp.
     
  5. Doc

    Doc Formula Junior

    Sep 13, 2001
    886
    Latham, New York
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    Bill Van Dyne
    Aside from the water pump, there are several clamps on connector hoses before and after the thermo housing and a hose from the long coolant pipe which runs next to the fuel tank . Check all of those hoses AND check the pipe itself, as recommended. The pipe on my 308 QV also developed a hole from rubbinig against the fuel tank strap. It would leak erratically depending upon temp.
     
  6. DGS

    DGS Four Time F1 World Champ
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    May 27, 2003
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    Air in the system can do weird things to the cooling system. For one thing, seeing a periodic jump then drop in the coolent temps is more likely air bubbles in the system than an indication of the t-stat opening.

    There are bleed valves on the radiator, and another on top of the thermostat housing. It can take several tries to get all the air out of the system without a pressure bleeder.

    A pressure bleeder will also tell you if the system is losing pressure from a leak somewhere.

    One thing you might want to check is that the radiator bleed valve is sealing. That might be a source of air getting into the radiator as the car cools.

    Another symptom to look for is high temperatures when running, with coolent overflowing after shutdown: that would indicate a bad head gasket.

    But you need to get the air out of the system before doing much else.
     
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  8. RussF

    RussF Karting

    Nov 1, 2003
    222
    Washington
    Thanks Guys. Helpful advice as usual. DGS when you talk about coolant overflowing from where do you mean?
     
  9. Darolls

    Darolls F1 Veteran
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    Jul 2, 2003
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    The only place overflow can occur is from the expansion tank.
     
  10. Russ: Maybe this will help you.

    It has been my experience that although you can bleed the air from the front radiator using the knurled screw, air will move back into this area. This was my experience as well as others and you may find it in the archives. Two common problems: People driving themselves crazy continually bleeding the radiator, and those who keep filling the expansion tank up above the mid-seam only to have the extra end up on the floor after a good run. (I learned this from experience :) )

    Make sure the radiator cap is sealing well, fill the reservoir to the seam, bleed the radiator, run the car for a few days, then adjust the fluid in the reservoir to the seam again when the engine is cold... and leave the radiator alone as there will always be a bit of air up there. Now, go chase your coolant leak!

    As was mentioned before, coolant tends to follow interesting paths. There are a couple of hoses on the right side that tend to swell and leak around the clamps. If I remember correctly, there are three short hoses... but it's been a while since I took a good look at a 328. If you have a leak in this area, it might make it's way down to the right rear wheel... not sure. The hose under the plenum is really fun to replace unless you have small hands.

    So, double check the cap... Buy a new one if necessary. Some head to the local parts store and pick up a Standt (#229 if I remember right) Buy a new thermostat. They are not as expensive as you might think. Leave the air in the radiator. Don't fill the reservoir above the seam when cold... which is about 1/2 full. Keep an eye on the hoses as they do swell and should be replaced from time to time. Enjoy your car.


    Best of luck to you.
     
  11. DGS

    DGS Four Time F1 World Champ
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    The expansion tank has an overflow line that feeds down near the left rear wheel (on US models). But head gasket leaks also tend to see higher than normal cooling system pressures (as the cylinder compression pumps into the cooling system) and associated higher coolant temps (higher boiling point).

    As it's August, perhaps I should mention that you need to turn your heater controls to full hot before bleeding, in order to get the air out of the heater cores, too. This often gets forgotten, even in pro shops.

    This can be highly variable. Sometimes the bleed valve will have trouble sealing, and will leak both ways. This is more of a problem when you bleed a hot radiator ... it doesn't want to seal again. I haven't had a problem on mine when doing the bleed cold.

    The expansion tank level can be tricky -- too much and it overflows, too little and the system can pull in air. I usually put in a bit too much and let the car spit out what it doesn't want. ;)
     
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  13. 285ferrari

    285ferrari F1 World Champ
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    Ok guys I now have another leak and need the hose that goes from the coolant tank to under the plenum. I checked the parts thread and did not see it. Is there a part number someone has that will match a NAPA or Gates, etc. hose. My mechanic said it looked like it gets bigger towards the plenum , like it is 3/4 on one end and bigger on the other... Not sure...
     
  14. mike

    mike Formula Junior

    Nov 2, 2003
    721
    Colorado
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    Russ,

    I too have the same leak on my '86 328. Tho coolant collects on the right rear passenger side, just forward the wheel. There is a heat shield on the exhaust pipe at this point also and coolant collects on the shield. Also on the same side there is another heat shield that is just above the exhaust heat shield and it wraps around toward the 5-8 bank header. It's funny that there is no coolant on this heat shield (and it sits above the exhaust pipe heat shield). I have cheked the weep holes on the water pump..dry..
    I checked the pipes, hoses, clamps around the right rear wheel, dry & tight. No weeping/coolant running down from pipes, I checked the thermostat housing...dry & tight.....head gaskets dry...

    I am at a loss, I thought at first it was the water pump, but it's dry and besides my experience has been that with a bad water pump, coolant generally collects on the heat shield for the 5-8 bank header...I completely removed that shield and found no coolant on it...(remember this shield sits ablove the exhaust pipe heat shield..
    I will try & post a diagram to show which shields I'm talking about..
    It just baffles me that the lower shield has coolant on it but not the one above it..especially since they are both, BELOW the engine..
    I too appreciate any suggestions...
     
  15. mike

    mike Formula Junior

    Nov 2, 2003
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    Of course I can't copy & paste but just so everone knows it's Tav 19 the manifold heat shield is part #'s 40 & 41...unfortunately the exhaust pipe heat shield is not show because it's hidden by part #'s 40 & 41..
    any help here with posting this page...
     
  16. 285ferrari

    285ferrari F1 World Champ
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    I just want the hose to replace it--Anybody have one for sale????
     
  17. wolftalk

    wolftalk Formula Junior

    Jan 27, 2004
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    phil
    the larger 3/4"-ish hose is just a 3/4" hose (close enough to the original metric). It terminates on a metal pipe just below the oil filter - it doesn't go under the plenum. The pipe it connects to is a larger diameter. I replaced mine with standard gates stuff (not green stripe...didn't want the extra stiffness).

    The upper/smaller hose on the coolant tank does go under the plenum, and the end under the plenum likes to mushroom a bit. I replaced that hose with standard stuff also, but don't recall the ID.
     
  18. peajay

    peajay Formula Junior

    Apr 17, 2002
    454
    near Paris, France
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    Paul
    I am in process of chaning ALL hoses on my 328 as preventive maintenance. Don't be too concerned about getting the Ferrari part number for the hose, just pull off the accessible end and check the inner diameter. Then go along to NAPA and get a length of good quality hose and replace it. I have already done many of mine and no problems at all. I presume you have already checked the aluninium pipe on the RHS to be sure the air scoop has not rubbed a hole in it ? this is a classic fault in the 328, I found mine had a good rub so re-adjusted to get clearance and stuck on a neoprene spacer for insurance. Goood luck !!
     
  19. Doc

    Doc Formula Junior

    Sep 13, 2001
    886
    Latham, New York
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    Bill Van Dyne
    Even though you haven't detected it, you still may have a pinhole in the coolant pipe which leads from the thermostat. I had the same issue w a 308QV. I only smelled/saw a little dab of coolant on the ground episodically--probably when the temp got higher and the coolant would expand more to reach the hole. Over time , the hole got bigger and I finally had a major eruption--at midnight in downtown Montreal on F1 weekend! That was a lot of fun. Also if the small hose under the plenum is beginning to leak, the 2 large hoses under there may also have minor leaks or will soon. Maybe you're getting a dribble from one of those hoses. That's a very hot area and those hoses are prone to break before many other ones on the car.
     
  20. 285ferrari

    285ferrari F1 World Champ
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    If you need this hose --Daniel at Ricambi can get it. Great price and quick. Called FOW they said 2-3 weeks from the factory. Yea right.
     

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