thunderace
|
| posted on 15/10/12 at 04:26 PM |
|
|
negative pressure help
When I say negative pressure, there is enough vacuum in the crankcase to make it difficult to remove the oil fill cap while the engine is idling (if i
remove the dip stick it sucks like a hover),the car has smoke or steam coming out the exhaust ,i have just fitted the engine over the weekend and its
a 2002 polo engine anyone any idear what the problem may be ? im going to do a compretion test tomorrow to see if its a blown head gasket but there is
no water in the oil and i dont think it loseing any water
|
|
|
|
|
Ben_Copeland
|
| posted on 15/10/12 at 04:57 PM |
|
|
Could be a blocked breather...
I thought blown gaskets made positive pressure not negative
Ben
Locost Map on Google Maps
Z20LET Astra Turbo, into a Haynes
Roadster
Enter Your Details Here
http://www.facebook.com/EquinoxProducts for all your bodywork needs!
|
|
|
T66
|
| posted on 15/10/12 at 05:06 PM |
|
|
When the Land Rover TD4 crankcase gauze filter blocked it created positive crank pressure and blew oil past the crankshaft seal.
Once cleaned and replaced with the BMW cyclone filter, it stopped dripping and all returned to normal.
Take the cap off and run the engine, and put your hand over the hole, suck or blow as they say ?
|
|
|
rusty nuts
|
| posted on 15/10/12 at 05:09 PM |
|
|
Blocked breather would cause positive pressure . The thing I can think of is a connection to the inlet manifold causing crankcase vacuum. Doubt if it
is due to low compression
|
|
|
daviep
|
| posted on 15/10/12 at 05:41 PM |
|
|
Sounds like PCV valve problem, I'm sure google will get you pictures and symptoms.
Cheers
Davie
“A truly great library contains something in it to offend everyone.”
|
|
|
coyoteboy
|
| posted on 15/10/12 at 08:05 PM |
|
|
Many cars run an electronically (or sometimes pneumatically) switched crankcase vent straight to the plenum. If your valving has failed it'll
suck most of its air through the crankcase. This is a problem on a number of levels.
|
|
|
GOJO
|
| posted on 15/10/12 at 09:06 PM |
|
|
Probably the diaphram in the oil breather,letting it suck crank gases instead of from air filter blank the manifold connection and vent the breather
to a catch tank
|
|
|
thunderace
|
| posted on 16/10/12 at 11:44 AM |
|
|
quote:
Originally posted by GOJO
Probably the diaphram in the oil breather,letting it suck crank gases instead of from air filter blank the manifold connection and vent the breather
to a catch tank
diaphram in the oil breather is fine it sucks from the breather pipe also
i have googled it and found nothing
|
|
|
thunderace
|
| posted on 16/10/12 at 03:30 PM |
|
|
done a compretion test and all was ok but all plugs were wet with oil (but i worked out the the oil was coming from the rocker breather into the
throttle body so thats no suprize)
|
|
|
daviep
|
| posted on 16/10/12 at 03:47 PM |
|
|
Which engine?
“A truly great library contains something in it to offend everyone.”
|
|
|
thunderace
|
| posted on 16/10/12 at 04:23 PM |
|
|
sorry its a 1L MPI engine
im going to remove all vacume hoses and flush them
[Edited on 16/10/12 by thunderace]
|
|
|
thunderace
|
| posted on 18/10/12 at 12:09 PM |
|
|
video
http://www.youtube.com/watch?v=D7nksEmK3EY&feature=g-upl
|
|
|
daviep
|
| posted on 18/10/12 at 01:34 PM |
|
|
The way the idle speed changes would suggest that it's definately linked to the inlet. Not much help sorry 
Cheers
Davie
“A truly great library contains something in it to offend everyone.”
|
|
|
froggy
|
| posted on 18/10/12 at 03:28 PM |
|
|
Older systems had a very small pipe to let any positive pressure into the inlet but later cars have a much larger flow rate , lots of bm,s do a
similar thing . Dirty breathers are common on these so clean them out and see how it drives . The idle valve compensates for the change in vac when
you open the filler and it still idles so its not a major issue . 
[IMG]http://i144.photobucket.com/albums/r187/froggy_0[IMG]
|
|
|
.jpg)
