Oil pump replacement on 5.3 vortec - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**Nima** · 12-06-2019, 09:27 PM

Hi Guys:
I am refreshing a 2003 5.3 vortec to transplant either in my truck or a 72 Nova. While I was at changing the seals and gaskets, I decided to replace the oil pump since engine came with 110,000 mile and inside the engine did not look as clean as I would like it to be.
Anyways, I just took the old one out and lined up the new one and put things back together. This morning I was reading a HOTROD magazine and I saw an article about this replacement and it mentioned that you have to alight the oil pump (there were two method mentioned)

How critical is this alignment? Is it a must do? I have put everything back together and I was ready to fabricated my engine mounts!
Thanks for the help

**hatzie** · 12-10-2019, 11:18 AM

There are several schools of thought on this.
I'd do it because it's so easy to do... especially with the engine on a bench or a stand.

Replace the O-ring, pickup tube, and strainer... I'd install a pickup tube girdle so it's being held onto the oil pump by two bolts not just one. One bolt was good enough for GM but they only build them so that 98% of them make it past the warranty. After the warranty runs out they really don't care.

68Gold/white · 01-12-2020, 09:10 PM

I have not done this, but I do know an oil pump alignment tool is something that is made for this job. I am sure Summit has one, I would invest in one. The new oil pump was a very good thing to do.
What condition is the timing chain???

**Nima** · 01-15-2020, 12:08 AM

I ended up calling Melling tech support since when I looked at their website, there were many videos including one about priming the new pump but there was nothing about aligning the pump. I thought if the pump alignment was important like priming the new pump, they would have some instruction or video about it. I was told by their tech that there is no need to align their pumps. The only thing is recommended if finger tight the bolts, rotate the engine by hand 360 degree and then torque to spec.

12-06-2019, 09:27 PM	#1
Nima Blue 67 Join Date: Apr 2004 Location: Western WA Posts: 1,169	Oil pump replacement on 5.3 vortec Hi Guys: I am refreshing a 2003 5.3 vortec to transplant either in my truck or a 72 Nova. While I was at changing the seals and gaskets, I decided to replace the oil pump since engine came with 110,000 mile and inside the engine did not look as clean as I would like it to be. Anyways, I just took the old one out and lined up the new one and put things back together. This morning I was reading a HOTROD magazine and I saw an article about this replacement and it mentioned that you have to alight the oil pump (there were two method mentioned) How critical is this alignment? Is it a must do? I have put everything back together and I was ready to fabricated my engine mounts! Thanks for the help __________________ 1953 GMC 3/4 ton: current project 1967 C20: 5.3 voretc with T5 conversion, 4 wheel 8 lug disc brake 1972 Nova: my 4 door sport sedan! 5.3 voretc + T5 conversion. drivable project, FUN!! 1979 Camaro Z28: 5.3 vortec conversion with build TH350: drivable project, Fun to drive 1992 Camaro RS convertible (Z28 clone): 5.3 conversion with build T5: on going project 2005 Silverado 2500, 4x4 Duramax, original owner

12-10-2019, 11:18 AM	#2
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,912	Re: Oil pump replacement on 5.3 vortec There are several schools of thought on this. I'd do it because it's so easy to do... especially with the engine on a bench or a stand. Replace the O-ring, pickup tube, and strainer... I'd install a pickup tube girdle so it's being held onto the oil pump by two bolts not just one. One bolt was good enough for GM but they only build them so that 98% of them make it past the warranty. After the warranty runs out they really don't care. __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful.

01-12-2020, 09:10 PM	#3
68Gold/white Registered User Join Date: Sep 2011 Location: Ark City, Kansas Posts: 3,272	Re: Oil pump replacement on 5.3 vortec I have not done this, but I do know an oil pump alignment tool is something that is made for this job. I am sure Summit has one, I would invest in one. The new oil pump was a very good thing to do. What condition is the timing chain???

01-15-2020, 12:08 AM	#4
Nima Blue 67 Join Date: Apr 2004 Location: Western WA Posts: 1,169	Re: Oil pump replacement on 5.3 vortec I ended up calling Melling tech support since when I looked at their website, there were many videos including one about priming the new pump but there was nothing about aligning the pump. I thought if the pump alignment was important like priming the new pump, they would have some instruction or video about it. I was told by their tech that there is no need to align their pumps. The only thing is recommended if finger tight the bolts, rotate the engine by hand 360 degree and then torque to spec. __________________ 1953 GMC 3/4 ton: current project 1967 C20: 5.3 voretc with T5 conversion, 4 wheel 8 lug disc brake 1972 Nova: my 4 door sport sedan! 5.3 voretc + T5 conversion. drivable project, FUN!! 1979 Camaro Z28: 5.3 vortec conversion with build TH350: drivable project, Fun to drive 1992 Camaro RS convertible (Z28 clone): 5.3 conversion with build T5: on going project 2005 Silverado 2500, 4x4 Duramax, original owner



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