GMCforum
For enthusiast of the Classic GMC Motorhome built from 1973 to 1978. A web-based mirror of the GMCnet mailing list.

Home » Public Forums » GMCnet » Engine oil dipstick tube mystery (A borescope would have come in handy, huh?)
Engine oil dipstick tube mystery [message #320860] Sat, 22 July 2017 21:27
LarryInSanDiego is currently offline  LarryInSanDiego   United States
Messages: 336
Registered: September 2006
Karma: 0
Senior Member
So I pulled the broken left exhaust manifold off and found the engine oil dipstick tube rusted through vertically. I know that sounds weird but the side facing the exhaust manifold was flat gone. Now that I was finally able to see how the heck it snaked between the exhaust manifold and cylinder head, I gingerly went to extract it as carefully as I could. It literally lifted right off, so I figured the rest was still in the block. This was a few months ago. So today, after reading how to pull out the rest, I went to try to determine the ID of what I thought was the remains of the tube in the block. First, I carefully inserted a pushrod (I had the heads off anyway) and was able to easily insert it ~8". I didn't want to letting it drop all the way in, so I pulled it back out and saw oil on the last inch or so. Hmm, I thought I saw pics on here where there was a turn in the part of the tube that goes through the block, so why didn't the pushrod stop sooner? Next, I carefully inserted several drill bits to determine the ID. Would the ID turn out to be the tube or the factory dipstick tube hole in the block? A 3/8" drill bit was as big as I was able to insert.

Since the pushrod didn't hit anything, I cut a wire coat hanger so that each end had a little bit of a hook left on it. This way I figured I could feel any "rings" that would make the tube fit tighter in the block as I had seen working on a friend's Cutlass - but of course, this is a FWD V8. The wire coat hanger went WAY in, picked up oil, and the only "catching" it had was a bit over an inch in, presumably the end of that block hole.

So where did the lower end of the tube go?

Did it:
A) fall all the way in at the hands of a PO?
B) was it never there to begin with, perhaps an earlier engine pull before I got it?
C) did my early '73 not come with a lower extension?
D) could it have rusted THAT deep?

Going straight in it obviously picked up oil. I'm just concerned that perhaps the lower portion was to guide it into a deeper part of the sump. I do remember the pic I saw on here showing how critical it is to properly align it so as not to have it or the dipstick itself collide with the crank (I'd use a stethoscope seeing how my engine is still installed). Any insight? Thanks in advance!


Larry Engelbrecht San Diego, CA '73 26' ex-Glacier TZE063V100319 03/07/73
Previous Topic: Couple more newbie questions
Next Topic: [GMCnet] Need a FD dip stick
Goto Forum:
  


Current Time: Thu Mar 28 10:37:39 CDT 2024

Total time taken to generate the page: 0.00753 seconds