Can an engine oil leak cause a fire?

[mechanic36]

Hi all! Same question as in automotive that I wrote a couple of days back, now modified with more detail.

Can an engine oil leak from a rocker cover gasket onto an exhaust manifold (NOT the cat) be the sole cause of an under bonnet fire? Flash point of oil is around 200 deg centigrade, temp of exhaust manifold is what at normal operating temp? (checked one the other day and found it to be 55 deg C - NOT up to full op temp though)

Thanks for any help.

 

[carnage]

yes it can cause a fire
please don't ask how I know
also the exahust manifold has to be over 600f ( i think could be C but that seems to high) internaly for an O2 sensor to work so reduce that tempature some to compensate for the cooling action of the air over the outside of the manifold.
but I am sure that the outside of the manifold could hit 200c especially if you were sitting in traffic.

 

[franzh]

In the mid 1980's, the US made the Pontiac Fiero with the 2.5 4 cyl pushrod engine which had a serious problem with the rocker cover leaking oil, especially on the exhaust manifold, and burning the engine. There were revised rocker covers made that reinforced that area, but ultimately, it took an engine redesign to solve that problem. The US made engines were notorious oil leakers up until the late 80's when they did some very significant redesign on traditional leak areas, rear seals, intake manifolds, rocker covers, etc. Many vehicles today go well over 100,000 miles with a dry engine.

Franz

 

[evelrod]

mechanic36---

The general consensus in both forums to which you have posted this same question is YES! YES, an oil leak CAN cause an underhood fire. YES ,a leaking rocker gasket can cause an underhood fire. You have read the other posts, you know by now that it has happened to me and to many others. I had forgotten about the Fierro GT problem, as I have seen SEVERAL burned wrecks, the result of oil fires!
As posted before, there is no specification that I have heard of as related to re-torquing the rocker covers during dealer, or for that matter, any normal service, oil change, or whatever.

Oh yes, the exhaust manifold CAN operate at 1200 to 1400 F.


Rod

 

[GregLocock]

Franz, the main reason that production engines are dry these days is that they run crankcase at vacuum, rather than at a slight positive pressure as they used to. Therefore any leaks are air into the engine rather than oil out. This was introduced around 1978 at British Leyland (I don't know who we copied it from).

In my brief but glorious(!) career as a maritime electrical designer I learnt that sealing against splashes with no net pressure difference is the hardest thing to do, basically you have to glue the seal to each surface.
Cheers

Greg Locock

 

[comnean]

Yes,
1. In the first section area, under fire wall, is possible to have a 600 C. If you want you can see the red color of exhaust manifold (very hot engine, in the dark)
Sorry for my english.