Valves...4100
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HT4100 4.1, 4.5, 4.9 Discussion, Valves...4100 in Cadillac Engine Technical Discussion; Hello, I have been having a problem on my Deville with a rough idle from time to time, and skipping ...
  1. #1
    GeneLaw1 is offline Cadillac Owners Fanatic
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    Valves...4100

    Hello,

    I have been having a problem on my Deville with a rough idle from time to time, and skipping during driving. I take it this place that specializes in Cadillacs and they claim "the valves are sticking and you need a $2000 valve job"......Anyone have any input on this?? The engine is the HT 4100 and has 52k miles on it, it was driven off and on and when I took possession of it, I noticed the rough idling a couple years ago. It seems to accelerate fine if thats any help.

    Gene

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    GeneLaw1 is offline Cadillac Owners Fanatic
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    Re: Valves...4100

    A little more information, I have done a FULL tune up, tried STP in the gas tank as well. The shop that diagnosed the valves say they did a cleaning of them with some chemical, but that did not work at all either.

  4. #3
    cadillac_al is offline Cadillac Owners Connoisseur
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    Re: Valves...4100

    A good shop would do a compression test if they thought there were bad valves. I would say it takes a darn good mechanic to get these heads off and back on again without problems and I wouldn't risk it. When the 4100 dies an early death like most do, it is time to replace it with something else. When was the last tune up on this car? Isn't there a service engine light and a digital information center on those cars so you can read codes?

  5. #4
    GeneLaw1 is offline Cadillac Owners Fanatic
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    Re: Valves...4100

    Quote Originally Posted by cadillac_al View Post
    A good shop would do a compression test if they thought there were bad valves. I would say it takes a darn good mechanic to get these heads off and back on again without problems and I wouldn't risk it. When the 4100 dies an early death like most do, it is time to replace it with something else. When was the last tune up on this car? Isn't there a service engine light and a digital information center on those cars so you can read codes?
    Apparently the place I went to was not a good shop, lol, because I do not think they did anything of the sort. There is a "service soon" light on the car and a "service now" on the car, neither of which have been triggered. I did a tune up about two months ago. There is a digital fuel center which can be read from inside the car, but not sure about the code thing. As for as dying an early death, I have seen many last well into 200k miles!! Guess its all about how you take care of it....

  6. #5
    Dave S Texas's Avatar
    Dave S Texas is offline Cadillac Owners Enthusiast
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    Re: Valves...4100

    If you intend to keep the car: you should buy the Cadillac Factory Service Manual. Should be some on ebay.

  7. #6
    ehall's Avatar
    ehall is offline Cadillac Owners Connoisseur
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    Re: Valves...4100

    you have the RWD 4.1 so all bets are off

  8. #7
    steelybill is offline Cadillac Owners Enthusiast
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    Re: Valves...4100

    I use Marvel Mystery Oil for sticky valves, and it works. It's worth a few bucks to try some, if in fact the problem is sticky valves. A pint in of it in the engine oil is what I would use.

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