Today replaced the flame trap on my 1990, been years or never since checked. Used Flame Trap Kit from IPD. Flame trap on 1990 located above intake manifold pipes 3 & 4. With finger twisting, was able to pull the upper belled end of the PCV hose off of the lower S hose, and then replace in reverse order. Observations: Old flame trap was not clogged, but orifaces reduced by carbon & gunk. It was degraded by heat and after removal, the sides started to crumble with minor pressure. The little 5mm hose going from plastic fitting over to the brass nipple on the intake manifold was totally deteriorated and pinched, so replaced it. 3-way plastic fitting broke in the removal process. From the IPD stuff replaced the plastic fitting and also the 5mm hose in addition to the flame trap. The S-shaped hose that goes down to the oil separator comes with the kit, but the existing one was ok, and very difficult to access and replace, thus left it alone.

Also, rigged a "blower" with a funnel hose and a nozzle from vacuum cleaner. Attached funnel hose to the S-hose on oil separator. Removed engine oil filler cap. Blew hard down the hose into the oil separator, and got good pressure coming out of the oil filler. Hopefully indicating that oil separator is not clogged.

Good that you learned about cleaning the flame trap before it caused problems, I wasn't so lucky! One other thing you should check, though, is the nipple on the intake manifold -- from your description of the hose going to it, there's a good chance that it's clogged up, too. Either take it off and clean it thoroughly or just find a stiff enough wire to go through it to clean it out.

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'81 GLT 245 @ 259K; '83 DL 175K

Mbliss, I inserted a pipe cleaner all the way into the intake manifold nipple without any resistance or carbon, crud, or oil etc coming out on it. The pipe cleaner came out clean and white with only a tiny bit of gray dust. Thus, it seems to be very clean. I think the hose was more heat degraded than actually clogged. Thanks.

Good job!

Take note:
Oil separator has two passages leading downward into crankcase.
So, blowing into it successfully (air comes out the oil fill opening OK) only guarantees that at least one of the two is open. If you don't find oil seeping from any seals, then you can suppose that all is well. The two passages are set up differently; one receives incoming mist/vapor and the other returns droplets to the crankcase. For details see
http://www.brickboard.com/FAQ/700-900/EngineSealsBeltsVent.htm#Crankcase_Ventilation_A_Treatise

In my case, I still had leaks after servicing the upper flame trap system, so I removed the separator and insured that all passages were open. While in the area, I cleaned the throttle body, Idle Air Control, and the flexible "accordion" intake hose. Still had a rear main seal leak so I paid my shop to replace that seal. Problem solved.
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Sven: '89 245, IPD sways, electric rad. fan conversion, 28+ mpg - auto tranny. 850 mi/week commute. '89 245 #2 (wifemobile). '90 244 (spare, runs).

Thanks, I have added your helpful information to my database on this topic. I have an occasional drop of oil at the back of the engine, we'll see how that evolves. I have no confidence that I could ever get to the oil separator from above, assume you have to remove the intake manifold to access that stuff?