I used the point & shoot thermometer to determine that the #3 glow plug on the '87 190D 2.5 turbo is useless. The other exhaust ports were getting to 80F and 90F but #3 was still 30F, until the cylinder finally decided to start firing. #1 also seemed a bit slow to warm up.

So I got 2 glow plugs and then looked at the job. Its impossible to get to #3 without removing the intake manifold. I may as well get 3 more glow plugs and do all of them at the same time.

So long as I'm gonna take off the manifold, is there anything I can do (within reason) to improve MPG, even a bit?

My goal with this car is to approach 40 MPG if possible, with little tweaks.

I put on a K&N air filter last week. The old filter was so crapped up, that change should be worth 3 to 4 MPG. Before that, I made a copper plate to block the ERG.

__________________
.
1st MBz: 1982 300SD
2nd MBz: 1987 300SDL
3rd MBz: 1995 S420
4th MBz: 1987 190DT
5th MBz: 1984 300SD w/1983 300DT engine
6th MBz: 1999 C230k I'm 3rd owner, got it w/57,235 miles.
and manages Mom's 2007 R320 CDI