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Cylinder head gasket

Discussion in '365 GT4 2+2/400/412' started by Ewan, Jan 11, 2019 at 2:34 AM.

  1. Ewan

    Ewan Karting

    Jul 5, 2015
    95
    Dorset, UK
    While there is very little evidence of emulsion/scum on inside of the engine oil cap on my car, there is quite a lot on the inside of the radiator cap. To the best of my knowledge (and extensive car history file paperwork), the engine in my car has never been out and the CYG has never been changed. Obviously this is quite a big and expensive job (I’ll be paying an independent Ferrari specialist to do it).

    Questions - does it sound like I have to do it now, and if so, what else is sensible (within reason) to do at the same time?
     
  2. wda24729

    wda24729 Formula Junior
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    Sep 22, 2014
    921
    Devon, UK
    Full Name:
    Graham
    #2 wda24729, Jan 11, 2019 at 3:26 AM
    Last edited: Jan 11, 2019 at 3:33 AM
    Hi Ewan, it might be worth just checking / replacing the O-rings in the oil filter housing first. These two small rings provide a seal between the oil route and water route in the centre of the block where they cross.

    There's a thread on here somewhere, but I'm rubbish with the search function!
     
  3. Temerian

    Temerian Karting
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    Jun 17, 2014
    124
    Manhattan
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    Rick Temerian
    Hi Ewan, what is the mileage on the car? I had the same issue and when I started to go through the engine the timing sprockets were completely worn as were the tensioner pads. My car has a little less than 100,000 K but likely never had the timing chain adjusted. For me it was worth pulling the engine and doing the timing chain work as well as valves, valve guides and pistons and rings. Mostly for peace of mind but also because I have very little knowledge of how the car was treated in the first 36 years of its' life. I also have been doing the brakes, bushings, shocks and engine bay while the motor work is being done. I'll try to post some photos soon. Good luck with the project!
     
  4. wrxmike

    wrxmike F1 Veteran
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    Mar 20, 2004
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    Michael
    https://www.ferrarichat.com/forum/threads/oil-in-coolant.376670/#post-141621921
     
  5. Newman

    Newman F1 World Champ
    Professional Ferrari Technician Owner Consultant

    Dec 26, 2001
    12,738
    Barrie, ON, Canada
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    Newman
    Auto or stick? If its auto the oil cooler in the rad could be contributing to oil in the coolant.
     
  6. rubenpadron

    rubenpadron Formula Junior
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    Oct 22, 2013
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    Ruben
    +1 to start with the O rings in the oil filter housing... this is easy and cheap, compared to a cylinder head gasket.

    Ruben
     
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  7. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
    24,089
    Austin TX
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    Brian Crall
    Almost never caused by a cylinder head gasket. Paul is correct. It can also be traced to the water pump on some of the engines. I cannot recall the architecture of the 365 water pump from memory.
     
  8. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
    24,089
    Austin TX
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    Brian Crall
    Actually I had to look it up the 400i had a stand alone trans cooler, radiator just cooled water, not sure about earlier models and the 365 used the radiator for cooling engine oil like the C4.

    I stand by earlier statement, the last place I'd consider was the head gaskets assuming a correctly assembled engine. 365 and up had very few head gasket issues except for the occasional external coolant seep.
     
  9. Ewan

    Ewan Karting

    Jul 5, 2015
    95
    Dorset, UK
    My car is an auto, from 1979, so one of early 400i autos. Mileage is 57,000.

    Certainly, checking/changing the O rings would be a no brainer. But given the CHG is now 40 years old, I’d be surprised if that was still shipshape.
     
  10. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
    24,089
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    Brian Crall

    Is CHG supposed to mean head gasket? Why not? And with logic like that I can make a case for a complete restoration.
     
  11. raemin

    raemin Karting

    Jan 16, 2007
    89
    Lyon (FR)
    Full Name:
    R. Emin
    Changing the cylinder head gasket is not without risks: the head is often "glued" on the engine block, they are somes protrusions on the head that ease the removal, but it is easy to break the head in the process, so the safest procedure is to use a dedicated head removal tool. apart from the tooling, parts are numerous (valves, guides, joints, rings, ...). All in all that's not a worry free maintenance job.

    As a side note: already seen 6 engines wide open, not a single one with failed or damaged gasket.
     
  12. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
    24,089
    Austin TX
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    Brian Crall

    365's just did not have head gasket problems. That said the OE supplier gaskets are now junk and another choice needs to be made.
     
  13. wrxmike

    wrxmike F1 Veteran
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    Compression test and coolant test for combustion gases and examining the spark plugs will let you know if you have a head gasket failure.
    As Brian said, ( and he would know) these engines don't have a reputation for cylinder head gasket failures, so don't assume they are the problem simply because the heads have not been off in 40 years.
     
  14. Ewan

    Ewan Karting

    Jul 5, 2015
    95
    Dorset, UK
    The two Ferrari mechanics (from different garages) that I have chatted to have both diagnosed the problem as being highly likely to have been caused by a failure of the gasket. So I think I’ve resigned myself to going ahead with this job, and possibly skimming the head (if required) at the same time. Naturally the O rings will be replaced also. Well also look at the valves and guides, though I really don’t want the job to escalate out of hand.

    The heater has also failed - the fans blow nicely, but the air coming out is not hot. So they’ll look at that while the car is in. Hopefully just a blockage in a pipe somewhere.

    Once this is all sorted, hopefully within a few weeks, the car is then booked in with the body shop for a full glass-out, bare metal strip down and full repaint, then fitted back with some new glass, rubbers, badges, etc. So, the next few months are going to be expensive for me.

    Still haven’t decided on the final colour either. It was originally ordered in Blu Ribot, but before it went into build the order was changed to Bruno Acajuo, so that’s the colour it was actually built. But after about 6 years, the owner got bored and had the local Ferrari dealer change it to Blu Sera, which is the paint still on it now. Decisions, decisions...
     
  15. Bill26

    Bill26 Karting
    Silver Subscribed Owner

    Jun 19, 2005
    163
    Australia
    Full Name:
    Bill Murdoch
    Ewan, without trying to be, in any way, antagonistic, I question the wisdom of launching into replacing the head gaskets.
    Has either of the mechanics actually seen the car/problem? Has either offered their reasons for their diagnosis?

    Replacing the oil filter plate ‘o’ rings is a relatively simple/cheap job to fix a known issue. Certainly worth considering. I really recommend that you read WRX Mike’s write up on this.

    Replacing the head gaskets is an engine out job with all of the associated likely ‘while you’re at it’ jobs. For a start, there is a good chance one or both heads will be stuck on the head studs and just removing them can be a major difficulty.

    Almost certainly, the valve guides will be shot and if the engine has never been apart, not replacing the sodium filled exhaust valves is beyond contemplation. Then there are all the other issues that will certainly present themselves. Once the job starts, you are committed to the expense (and the time).

    If the ‘o’ring replacement doesn’t fix the problem and you don’t want to commit to an engine rebuild at this time, why not just put up with the issue until you are ready? Oil in the water won’t do any real harm (unlike water in the oil).

    Good luck whatever you decide to do.

    WM
     
  16. Ewan

    Ewan Karting

    Jul 5, 2015
    95
    Dorset, UK
    Both mechanics have inspected the car, and were concerned about the amount of emulsion appearing in the coolant - even immediately after an empty and flush through. I think that was their main reason for recommending the work. And that both have had to do this job many times on this era of V12 Ferrari engine, including on 365/400/412 models.

    On the one hand, I don’t want to open a can of worms. On the other, I want the engine to run well, and for the coolant to be clear and efficient. Tricky decision right now.
     

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