PistonHeads.com Forum

Burning Oil

Author
Discussion

Collaudatore

Original Poster:

817 posts

114 months

Wednesday 14th October 2009
quotequote all
frown

MK1 MX5 ownership not feeling so sweet now.
Noticed a little puff of something as I was driving yesterday and checked the oil today - almost at minimum. There doesn't appear to be anything leaking, nor was there anything leaking when it was almost full when I bought it.

Again.... frown

What could the problem be? Anything else I could check to help diagnose?

pbirkett

10,373 posts

184 months

Wednesday 14th October 2009
quotequote all
CAS O-ring? Common fault, mine was leaking when i got mine. Cheap to repair.

Gizmo!

18,150 posts

121 months

Wednesday 14th October 2009
quotequote all
pbirkett said:
CAS O-ring? Common fault, mine was leaking when i got mine. Cheap to repair.
Mine too. I thought I could smell something when it was warming up, turned out it was split. Very easy fix.

Collaudatore

Original Poster:

817 posts

114 months

Wednesday 14th October 2009
quotequote all
Cheers guys. I'll go get my hammers and let you know how it goes.

5paul5

664 posts

83 months

Thursday 14th January 2010
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Think i have the same problem with mine, it smokes a bit on the overrun from the exhaust. Could it be the CAS O ring and where do i find it ?
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WarrenG

306 posts

109 months

Thursday 14th January 2010
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I babied out on the last week of snow driving, and noticed a nice plume of blue on startup, from stone-cold after a week's idle.

It doesn't do it on a startup on a morning cold, following a drive the previous day, but always after a few days not driven. is that related to the CAS O-ring (Crank Angle Sensor?) or is it just ring-pump on a cold, worn engine?

DennisTheMenace

15,581 posts

180 months

Thursday 14th January 2010
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5paul5 said:
Think i have the same problem with mine, it smokes a bit on the overrun from the exhaust. Could it be the CAS O ring and where do i find it ?
I would say its more likely to be valve stem seals or the rings on no.4 piston letting oil past .

MX-5 Lazza

7,802 posts

131 months

Friday 15th January 2010
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CAS O-ring failing causes an oil-leak that can trickle down onto the exhaust manifold so give a little under-bonnet smoke but usually just causes oil-drips on your driveway. It won't have anything to do with smoke from the exhaust.

Edited by MX-5 Lazza on Friday 15th January 08:37

dylan0451

1,036 posts

103 months

Friday 15th January 2010
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DennisTheMenace said:
the rings on no.4 piston letting oil past .
sorry, quick hijack...

is it that common for no.4 to start burning oil?

i was looking at the coolant re route kit FM do as part of my base upgrades before i consider more power, but wasn't sure it it was worthwhile

bluetone

2,043 posts

131 months

Saturday 16th January 2010
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MX-5 Lazza said:
CAS O-ring failing causes an oil-leak that can trickle down onto the exhaust manifold so give a little under-bonnet smoke but usually just causes oil-drips on your driveway. It won't have anything to do with smoke from the exhaust.
^^^ What Lazza said.

Don't tend to 'hear' (on fora) of many smoky exhausts tbh..