XJR - White Smoke at Start-up
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XJR - White Smoke at Start-up
This Forum has been very useful to me over the years and now it is time to return the favour.
I have read many ideas on this fault, but the answer is:
The exhast system with age starts to absorb water vapour when hot, when the exhausts cools it turns back to water and collects at the lowest point in the back-boxes.
Simply drill a 3mm hole at the lowest point of each back-box, the water then drains as it cools and next time you start from cold, no white smoke !
This fault really worried me and I thought the engine was on the way-out like many people, but often the cure is so simple.
Hope this helps others out in a similar position.
Oli Sherwood.
I have read many ideas on this fault, but the answer is:
The exhast system with age starts to absorb water vapour when hot, when the exhausts cools it turns back to water and collects at the lowest point in the back-boxes.
Simply drill a 3mm hole at the lowest point of each back-box, the water then drains as it cools and next time you start from cold, no white smoke !
This fault really worried me and I thought the engine was on the way-out like many people, but often the cure is so simple.
Hope this helps others out in a similar position.
Oli Sherwood.
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Joined: Sep 2009
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Oli and All,
If drilling holes solved the problem then it was most likely water vapor causing white smoke at start up. However, I seem to recall that a brake fluid leak can cause the same symptom.
It goes like this; brake fluid leaks from around the master cylinder actuating rod and accumulates in the brake vacuum booster. On start up, this fluid is sucked into the engine via the vacuum line and causes "white" smoke. Sometimes the fluid leaks is so small that one doesn't realise how much fluid is being added at regular service intervals by the owner and various service techs.
Hope this helps sombody.
If drilling holes solved the problem then it was most likely water vapor causing white smoke at start up. However, I seem to recall that a brake fluid leak can cause the same symptom.
It goes like this; brake fluid leaks from around the master cylinder actuating rod and accumulates in the brake vacuum booster. On start up, this fluid is sucked into the engine via the vacuum line and causes "white" smoke. Sometimes the fluid leaks is so small that one doesn't realise how much fluid is being added at regular service intervals by the owner and various service techs.
Hope this helps sombody.
Veteran member
Joined: Mar 2007
Posts: 11,344
Likes: 1,164
From: Oak Ridge, TN
Oli, thanks for the post, it sounds like it worked for you, and makes sense. I think the XJ has more than one true cause for fluffy clouds on startup. Yours sounds like the easy kind. 
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Joined: Sep 2009
Posts: 13
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From: USA NJ
transmition output input speed sensors HELP!!!
Hi, I have a 1998 XJ8 and the trany is giving me problems the code that i am getting is P1772 i think I have to replace the transmition output input speed sensors. but I cant find them any where. does anyone knows where i can find them and how much do they cost??
Thanks in advance
Thanks in advance
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