drpokey

Just wondering if anyone knew what size bit to use to drill out the oil dipstick boss on a 5.3 engine... I used the search function and couldn't come up with an answer. Couple of references to it being "metric", but nothing specific. Doing this on an 04 alluminum 5.3. Any tips on drilling this perfectly perpindicular??? Any help would be appreciated, thanks in advance.

John McGraw

Are you sure it is not just plugged? I have never used a truck block, but all the other aluminum blocks that I have used that did not have a dipstick in the block, just had a expansion plug driven into the hole. I just took a punch and punched them out.



Regards, John McGraw

drpokey

No, it definately needs to be drilled, its the alluminum truck block, came out of an envoy....

S10xGN

iTrader: (11)

Never seen one NOT drilled... I have an L92 block on the stand, the hole is 0.370" diameter and I could not imagine trying to drill one by hand.

Pocket

iTrader: (22)

Flip the engine over and drill from the pan side

Never seen one that needed to be drilled either. All had the knock-out

lizeec

iTrader: (57)

I have never seen one that needed to be drilled out, but then again "never say never" I think you need to look at it really good and you should see a little bitty freeze plug in there and you just use a punch and knock it out for the dipstick installation.

drpokey

I'm a little confused at this point... I can clearly see the boss for the dipstick on the lower edge of the back third of the passenger side of the engine... no freeze plug. However, I've not taken the oil pan off yet. So.... are you guys saying that from inside looking out, that the boss is mostly drilled??? Because there is definately no plug externally. I'll post a pic for additional help. Thanks for all the replies.

lechez71

iTrader: (1)

believe me it has a plug i have an 07 5.3L from an envoy denali also it had a front sump pan with the dip stick on the pan. i had to get a new truck pan to clear the frame. you have to remove the pan and hit it out. no need to drill it out.

drpokey

So, here is the pic I promised. So, is the passage drilled 90% throught from inside the oil pan?? Why would it not be drilled all the way through and then plugged from outside???

Any comments appreciated.

lechez71

iTrader: (1)

it is drilled all the way through and plugged from the outside. you will see the hole on the block when you remove the oil pan. take a center punch and knock it out from the inside out.

drpokey

So.... I posted this question a few weeks ago and didn't get any great answers other than "It's already drilled , just knock out the plug". While this may be true for the 06? and up alumimum 5.3s, it is most certainly not true of mine, which is an 04. This can clearly be seen in the picture I posted above.

Anyway, the short answer is that the hole, which I would be quite sure is metric, is closest to a 3/8" bit, the next size up is a 25/64 and that's too big. I used the 3/8" after drilling a pilot hole with 5/32" and the dipstick fits nicely, snug but not too tight. Hope this helps someone else.

Biggyniner

Thank you, Thank you, Thank you, for posting your follow up. This will help me out immensely. I am planning on doing an LM4 swap in a Volvo 760 and I needed to know this very thing... Here is some more detail on the LM4 not being drilled and plugged at the factory. It seems it was about the only engine family that was done this way! http://www.trifive.com/forums/archiv...p/t-81447.html

Project GatTagO

iTrader: (7)

I can confirm that the Gen III aluminum block 5.3L engines most definitely do not have the hole drilled in the block. I had an 04 5.3L aluminum block engine and it did not have the hole. A buddy of mine got one as well, and it did not have the hole drilled either. As I recall, when I drilled the hole, I used a 3/8" drill bit. I did it from the top with the pan off, no drama.

Andrew

Loco27

Pictures, do you still have the pictures of when you drilled it?

Project GatTagO

iTrader: (7)

I do not have any pictures. However, I recall that the process was not that complicated. There is a pad that is cast into the block where the dipstick needs to go. Just drill square to that pad.

I can also say that I have a GenIV aluminum engine (LH8) and it did have a hole in the block. But I had to use a plug (there is a GM plug for this...PN in my Cougar build thread) to plug it up, because I am using the front sump GTO pan, which has the dipstick in the pan.

Andrew

33willys

iTrader: (1)

I have an 2003 LM4 and it did not have a hole just like Andrews'. I just measured the end of a Lokar dipstick and drilled the hole to fit. No problem at all. Sorry, can't remember the size.