Different dipstick tube diameters for automotive and marine Chevy blocks

[dlogvine]

I found a very strange difference between marine and automotive Chevy 4.3 v6 blocks. The dipstick tube for marine block is a little wider than such for the automotive block and does not fit. I tried it in both prevortec and vortec automotive engines, rebuilt for marine use. None of the dipstick marine tubes fit. Is it the same for the other Chevy automotive and marine blocks? And how much different are these tubes?

 

[Scott06]

I think typically marine engines are made of same block on same line as Chevy truck engines, don’t think there is a marine engine block. I would suspect the differences you are seeing are related to something else like different casting numbers and or design revisions. For example my boat had a 090M casting 4.3 block, M means metric as in some of the bolts holes are metric (flywheel cover, side motor mounts); all other holes are US sizes. There is a 90 casting tat doesn’t have any metric threads. Not sure why...

 

[dlogvine]

I tried two different tubes from marine block in the automotive engines, none fit in. Both tubes from the automotive applications fit perfectly, I just got the second tube from automotive engine and it gets in without any difficulty. I had a strong impression that the blocks were the same for both applications. Will make pics tomorrow and post them online.

 

[racerone]

Perhaps it is due to the fact that on marine applications the tube is also used to WITHDRAW the oil during an oil change.

 

[dlogvine]

Perhaps it is due to the fact that on marine applications the tube is also used to WITHDRAW the oil during an oil change.

possible, marine tube is a little wider and from visual inspection has slightly thicker walls, maybe to better withstand outside water (maybe salt water) corrosion?

 

[alldodge]

What year oil pans are you working with?

 

[dlogvine]

What year oil pans are you working with?

One oil pan is original and belongs to 2001 or 2002 Chevy Blazer 4.3 v6 vortec engine, the other is not original, but marine oil pan for prevortec mercruiser 4.3. Year is unknown.

 

[Scott Danforth]

You do have to drive or press the dipstick in place