850 engine pressure build-up

efkaba · Post by **efkaba** » 21 Jul 2018, 11:07

1995 850 GLT non-turbo, 158,580 miles. Replaced the breather system at 157,036 miles because I noticed oil accumulating on the lower half of the engine when I changed the oil, and the glove test which I saw posted on Robert's DIY video indicated that pressure was building in the engine. Everything was fine after the replacement, did not see any oil leakage, and there was no pressure building in the engine as indicated by the glove test. Within the last couple hundred miles or so, I noticed some oil collecting around the bottom of the engine again, and it seems to be getting worse. I did the glove test, and the engine is building pressure again. I am pretty positive I thoroughly cleaned the port on the side of the engine where the breather box connects, so I am not sure why I am again having this problem. Purchased the OEM breather box kit from FCP Euro. Any help with this problem would be greatly appreciated.

DeathRex · Post by **DeathRex** » 21 Jul 2018, 14:20

Did you replace the hoses?

Post by **FLXC90** » 21 Jul 2018, 14:40

Do dry compression test, note results, if there's a large variance between cylinders do a wet test to check condition of rings. You may have blow-by that the breather can't keep up with in its stock configuration. You may need to upgrade to larger hose per the "Ultimate PCV" thread here.

efkaba · Post by **efkaba** » 21 Jul 2018, 20:13

DeathRex wrote: ↑21 Jul 2018, 14:20 Did you replace the hoses?

Yes I did.

efkaba · Post by **efkaba** » 21 Jul 2018, 20:16

FLXC90 wrote: ↑21 Jul 2018, 14:40 Do dry compression test, note results, if there's a large variance between cylinders do a wet test to check condition of rings. You may have blow-by that the breather can't keep up with in its stock configuration. You may need to upgrade to larger hose per the "Ultimate PCV" thread here.

Thanks, I will do that. I did notice an occasional odor of blow-by fumes while driving.

dj_v70 · Post by **dj_v70** » 22 Jul 2018, 11:48

Likely that either your pcv vacuum (hose to intake manifold) is clogged or you didn’t clean the bottom pcv port to engine as well as you think you did. This port clogs after 90 degree bend down to oil pan. Many remove oil pan to clean it. I dumped a qt of gunk oil flush down the port to clean it and then changed oil

efkaba · Post by **efkaba** » 22 Jul 2018, 12:17

thanks, I am going to remove everything and recheck the oil return port in the block. Also read about replacing the vacuum line to the intake manifold with a 5/8-inch heater hose. Thinking about doing that.