Pontiac GTO Forum banner
1 - 14 of 14 Posts

· Registered
Joined
·
7,355 Posts
Discussion Starter · #1 ·
The question of oil and filter capacity has been asked a couple times here in clarifying the correct amount. The confusing part is that some will say 5 quarts in the pan plus 1 for the filter making it a 6 quart system. BUT, another person may say that the correct amount is 6 quarts in the pan and 1 for the filter making it a 7 quart system - and they would be right based on the year of their GTO and/or the dipstick pulled from their engine. This conflicting info deals with the 1965-67 model years.

With the introduction of the 400CI, all Pontiacs seem to use 5 quarts in the pan and 1 quart for the filter. I have not compared the 389 to 400 heads with regards to oil return holes/passages which may have been redesigned when the new 400CI engines/heads came out, and thus the fix for the extra oil that was being held up in the top end of the engine.

A service bulletin was issued by Pontiac in 1966. It clearly states that the oil capacity is 6 quarts in the pan and 1 quart in the filter. GTO owners will tell you that their dipstick clearly says 6 Quarts at the fill line. Yet when a 5-quart dipstick is set side-by-side with a 6-quart marked dipstick, they are identical in length. There is no difference in the pan, they are all seemingly the same. Hmmm, so what gives?
I believe it was a PY forum member who stated that he had talked with Milt Schronack of Royal Pontiac fame and Milt said that Pontiac was replacing a lot of 1965 GTO engines under warranty and it was found that the engines were being burnt up due to lack of oil. The owners were pushing the engines hard and at the upper RPM's much of the oil was being pumped up to the top end and not leaving enough in th pan to oil the bottom end - especially if the oil level fill level had been allowed to get low. So Pontiac issued a service bulletin to fill all engines with 6 quarts plus 1 quart for the filter. They also used a dipstick having the 6-quart fill mark. This extra quart helped keep enough oil in the pan and prevent the engine from running out of oil and burning up.

So this bulletin and change was for 1966, but owners of 1965 and 1967 GTO's have also found the 6-Qt stamped dipstick. It is quite possible that when the car was brought to a dealership to be serviced and the oil/filter changed, the 5-Qt dipstick was replaced with the 6 Qt stamped dipstick so as to protect Pontiac from having to cover warranty engine work.

So it boils down to that Pontiac used a 5 quart pan and a 1 quart filter for 6 quarts, but increased the pan fill on their earlier cars to cover them from having to do engine warranty work due to those individuals who ran their engines hard, or raced them, and burned up the bottom ends due to low oil levels.

Pic #1 is the Pontiac bulletin.

So how high is the fill level of oil when it is in the pan? Nobody seems to know. BUT, now you do!! I used my 1973 factory pan having the oil baffle to see just what the oil level is within the pan. The pan was made level for this test. I filled and measured for 3 Quarts, 4 Quarts, and 5 Quarts. Keep in mind that this is at rest and once the engine fires up, oil gets pumped through the engine and the 5 Quart fill level will drop.

I will have a few follow up topics covering the factory oil baffle and my hand at extending the 1973 baffled oil pan in the photos for more oil capacity and adding the extended oil pump pick-up tube/screen to match. Got it all done and it was a ton of work, a lot of hours, and I would not recommend anyone doing this as I can assure you it would be easier and much simpler to just order an aftermarket oil pan having the additional oil capacity. Me?, I'm cheap, can do the fabrication work, and wanted to keep with "old school" practices that were done when a good aftermarket pan wasn't available or it was too expensive for the average car guy - like me when I was younger. (y)



Text Font Document Line Handwriting
 

· Registered
Joined
·
7,355 Posts
Discussion Starter · #2 ·
The question of oil and filter capacity has been asked a couple times here in clarifying the correct amount. The confusing part is that some will say 5 quarts in the pan plus 1 for the filter making it a 6 quart system. BUT, another person may say that the correct amount is 6 quarts in the pan and 1 for the filter making it a 7 quart system - and they would be right based on the year of their GTO and/or the dipstick pulled from their engine. This conflicting info deals with the 1965-67 model years.

With the introduction of the 400CI, all Pontiacs seem to use 5 quarts in the pan and 1 quart for the filter. I have not compared the 389 to 400 heads with regards to oil return holes/passages which may have been redesigned when the new 400CI engines/heads came out, and thus the fix for the extra oil that was being held up in the top end of the engine.

A service bulletin was issued by Pontiac in 1966. It clearly states that the oil capacity is 6 quarts in the pan and 1 quart in the filter. GTO owners will tell you that their dipstick clearly says 6 Quarts at the fill line. Yet when a 5-quart dipstick is set side-by-side with a 6-quart marked dipstick, they are identical in length. There is no difference in the pan, they are all seemingly the same. Hmmm, so what gives?
I believe it was a PY forum member who stated that he had talked with Milt Schronack of Royal Pontiac fame and Milt said that Pontiac was replacing a lot of 1965 GTO engines under warranty and it was found that the engines were being burnt up due to lack of oil. The owners were pushing the engines hard and at the upper RPM's much of the oil was being pumped up to the top end and not leaving enough in th pan to oil the bottom end - especially if the oil level fill level had been allowed to get low. So Pontiac issued a service bulletin to fill all engines with 6 quarts plus 1 quart for the filter. They also used a dipstick having the 6-quart fill mark. This extra quart helped keep enough oil in the pan and prevent the engine from running out of oil and burning up.

So this bulletin and change was for 1966, but owners of 1965 and 1967 GTO's have also found the 6-Qt stamped dipstick. It is quite possible that when the car was brought to a dealership to be serviced and the oil/filter changed, the 5-Qt dipstick was replaced with the 6 Qt stamped dipstick so as to protect Pontiac from having to cover warranty engine work.

So it boils down to that Pontiac used a 5 quart pan and a 1 quart filter for 6 quarts, but increased the pan fill on their earlier cars to cover them from having to do engine warranty work due to those individuals who ran their engines hard, or raced them, and burned up the bottom ends due to low oil levels.

Pic #1 is the Pontiac bulletin.

So how high is the fill level of oil when it is in the pan? Nobody seems to know. BUT, now you do!! I used my 1973 factory pan having the oil baffle to see just what the oil level is within the pan. The pan was made level for this test. I filled and measured for 3 Quarts, 4 Quarts, and 5 Quarts. Keep in mind that this is at rest and once the engine fires up, oil gets pumped through the engine and the 5 Quart fill level will drop.

I will have a few follow up topics covering the factory oil baffle and my hand at extending the 1973 baffled oil pan in the photos for more oil capacity and adding the extended oil pump pick-up tube/screen to match. Got it all done and it was a ton of work, a lot of hours, and I would not recommend anyone doing this as I can assure you it would be easier and much simpler to just order an aftermarket oil pan having the additional oil capacity. Me?, I'm cheap, can do the fabrication work, and wanted to keep with "old school" practices that were done when a good aftermarket pan wasn't available or it was too expensive for the average car guy - like me when I was younger. (y)



View attachment 137479
Here are the levels of the oil in the pan as measured from the bottom and the depth from the top of the oil pan rail to the oil level. I don't have photos of the 1-quart or 2-quart levels, just the measurements. You will see photos of 3, 4, & 5 quart fills.

Pontiac Factory Oil Pan with Oil Baffle - Measurement of oil levels based on quart capacity - 5 Qt pan. Pan bottom has a taper - 7 3/8 Front to 7 " Rear.

1 Qt Oil - From top of pan rail to oil level - 6"
Depth of oil at oil level to bottom of pan - 1 3/4"

2 Qts Oil - From top of pan rail to oil level - 5 1/2"
Depth of oil at oil level to bottom of pan - 2 1/2"

3 Qts Oil - From top of pan rail to oil level - 4 7/8"
Depth of oil at oil level to bottom of pan - 2 3/8"

4 Qts Oil - From top of pan rail to oil level - 4 1/8"
Depth of oil at oil level to bottom of pan - 2 7/8"

5 Qts Oil - From top of pan rail to oil level - 3 3/4"
Depth of oil at oil level to bottom of pan - 3 1/4"
Oil level depth above baffle and across front of pan extension - 5/8"
 

· Registered
Joined
·
7,355 Posts
Discussion Starter · #3 ·
Here are the levels of the oil in the pan as measured from the bottom and the depth from the top of the oil pan rail to the oil level. I don't have photos of the 1-quart or 2-quart levels, just the measurements. You will see photos of 3, 4, & 5 quart fills.

Pontiac Factory Oil Pan with Oil Baffle - Measurement of oil levels based on quart capacity - 5 Qt pan. Pan bottom has a taper - 7 3/8 Front to 7 " Rear.

1 Qt Oil - From top of pan rail to oil level - 6"
Depth of oil at oil level to bottom of pan - 1 3/4"

2 Qts Oil - From top of pan rail to oil level - 5 1/2"
Depth of oil at oil level to bottom of pan - 2 1/2"

3 Qts Oil - From top of pan rail to oil level - 4 7/8"
Depth of oil at oil level to bottom of pan - 2 3/8"

4 Qts Oil - From top of pan rail to oil level - 4 1/8"
Depth of oil at oil level to bottom of pan - 2 7/8"

5 Qts Oil - From top of pan rail to oil level - 3 3/4"
Depth of oil at oil level to bottom of pan - 3 1/4"
Oil level depth above baffle and across front of pan extension - 5/8"
3-Quart Fill

Metal
Blue Yellow Art
 

· Registered
Joined
·
7,355 Posts
Discussion Starter · #7 ·
I didn't want this post to get lost in the forum as it kinda relates to the pan fill levels. And I spent 200 hours and a $100,000 government grant to come up with the answer. ;)

 

· Premium Member
Joined
·
1,128 Posts
I made this same post in your thread about the heads.

The E-heads have a much more restrictive oil return back to the pan. I added an extra drain to try to help this situation. I don't have a picture of the drains in the heads, but I've attached a picture of the drain line I added to my engine.

Auto part Engine Automotive engine part Vehicle
 

· Registered
Joined
·
7,355 Posts
Discussion Starter · #9 ·
I made this same post in your thread about the heads.

The E-heads have a much more restrictive oil return back to the pan. I added an extra drain to try to help this situation. I don't have a picture of the drains in the heads, but I've attached a picture of the drain line I added to my engine.

View attachment 138224
Good info as I have not seen any other info on the E-heads but read there were some oil drain issues. I suspect this would only apply to a race type use engines and not a street engine? I'd hate to pay what they get for the E-heads and then have to modify as you have for the street. :(
 

· Premium Member
Joined
·
1,128 Posts
It should be fine for the street, but at high RPM the heads don't drain well enough. They just have small drain holes, no open passages. Just two holes if I remember correctly. If you wanted to check the valves after a race, oil would probably go over the edge of the head and onto the engine. You have to wait a bit before taking off the valve cover off.
 

· Registered
Joined
·
30 Posts
The question of oil and filter capacity has been asked a couple times here in clarifying the correct amount. The confusing part is that some will say 5 quarts in the pan plus 1 for the filter making it a 6 quart system. BUT, another person may say that the correct amount is 6 quarts in the pan and 1 for the filter making it a 7 quart system - and they would be right based on the year of their GTO and/or the dipstick pulled from their engine. This conflicting info deals with the 1965-67 model years.

With the introduction of the 400CI, all Pontiacs seem to use 5 quarts in the pan and 1 quart for the filter. I have not compared the 389 to 400 heads with regards to oil return holes/passages which may have been redesigned when the new 400CI engines/heads came out, and thus the fix for the extra oil that was being held up in the top end of the engine.

A service bulletin was issued by Pontiac in 1966. It clearly states that the oil capacity is 6 quarts in the pan and 1 quart in the filter. GTO owners will tell you that their dipstick clearly says 6 Quarts at the fill line. Yet when a 5-quart dipstick is set side-by-side with a 6-quart marked dipstick, they are identical in length. There is no difference in the pan, they are all seemingly the same. Hmmm, so what gives?
I believe it was a PY forum member who stated that he had talked with Milt Schronack of Royal Pontiac fame and Milt said that Pontiac was replacing a lot of 1965 GTO engines under warranty and it was found that the engines were being burnt up due to lack of oil. The owners were pushing the engines hard and at the upper RPM's much of the oil was being pumped up to the top end and not leaving enough in th pan to oil the bottom end - especially if the oil level fill level had been allowed to get low. So Pontiac issued a service bulletin to fill all engines with 6 quarts plus 1 quart for the filter. They also used a dipstick having the 6-quart fill mark. This extra quart helped keep enough oil in the pan and prevent the engine from running out of oil and burning up.

So this bulletin and change was for 1966, but owners of 1965 and 1967 GTO's have also found the 6-Qt stamped dipstick. It is quite possible that when the car was brought to a dealership to be serviced and the oil/filter changed, the 5-Qt dipstick was replaced with the 6 Qt stamped dipstick so as to protect Pontiac from having to cover warranty engine work.

So it boils down to that Pontiac used a 5 quart pan and a 1 quart filter for 6 quarts, but increased the pan fill on their earlier cars to cover them from having to do engine warranty work due to those individuals who ran their engines hard, or raced them, and burned up the bottom ends due to low oil levels.

Pic #1 is the Pontiac bulletin.

So how high is the fill level of oil when it is in the pan? Nobody seems to know. BUT, now you do!! I used my 1973 factory pan having the oil baffle to see just what the oil level is within the pan. The pan was made level for this test. I filled and measured for 3 Quarts, 4 Quarts, and 5 Quarts. Keep in mind that this is at rest and once the engine fires up, oil gets pumped through the engine and the 5 Quart fill level will drop.

I will have a few follow up topics covering the factory oil baffle and my hand at extending the 1973 baffled oil pan in the photos for more oil capacity and adding the extended oil pump pick-up tube/screen to match. Got it all done and it was a ton of work, a lot of hours, and I would not recommend anyone doing this as I can assure you it would be easier and much simpler to just order an aftermarket oil pan having the additional oil capacity. Me?, I'm cheap, can do the fabrication work, and wanted to keep with "old school" practices that were done when a good aftermarket pan wasn't available or it was too expensive for the average car guy - like me when I was younger. (y)



View attachment 137479
It should be fine for the street, but at high RPM the heads don't drain well enough. They just have small drain holes, no open passages. Just two holes if I remember correctly. If you wanted to check the valves after a race, oil would probably go over the edge of the head and onto the engine. You have to wait a bit before taking off the valve cover off.
I am now more confused then ever. I have a '67 with headers and thinner oil filter. How much should I use with an oil change? Thanks!
 

· Registered
Joined
·
7,355 Posts
Discussion Starter · #13 ·
I am now more confused then ever. I have a '67 with headers and thinner oil filter. How much should I use with an oil change? Thanks!
READ THIS POST!!!!!!

 

· Registered
Joined
·
7,355 Posts
Discussion Starter · #14 ·
READ THIS POST!!!!!!

Thanks to geeteeohguy for comparing his 1965 389CI 5-Quart dipstick with his 1967 400CI 6-Quart dipstick which show that the ADD lines are the same for each stick, but the FULL lines are where the difference is found. It is easy enough to see the space between ADD and FULL with the 6-Qt FULL line being more than 1 Qt low at the ADD line.

This adds validity to Milt Shornack's statement that Pontiac stamped the 6-Qt dipsticks to keep more oil in the same 5-Qt pan in an effort to minimize engine Warranty replacement due to oil levels getting to low and the engine starving for oil under hard acceleration.

Here is some added info:

AMA Specs for 1964 full size does show 4 qt pan +1 filter and the optional 5 qt pan +1 filter for the Optional 421 engines. The Tempest models also used a 4 qt pan.

1965 AMA Specs show 5 qt pan +1 filter.

1966 AMA Spes show 5 qt pan +1 filter BUT, read the clipping below.

1967 AMA Tempest Specs (8-26-1966) show 5qt pan +1 filter AND 6qt pan +1 filter for the Option Engines on the Lemans/Tempest Safari, and GTO. Optional engines are listed as the 400 HO and Ram Air 400. Firebird Specs (12-23-1966) show 6 qts pan +1 filter for Firebird 400 and Ram Air engines, and AMA Specs for B-Body engines show 6 qts pan +1 filter.

1968 AMA Specs are back to 5 qts pan +1 filter for all models.

A parts cross-reference book shows only 3 oil pans were used on the GTO with the book only covering up to 1972 - 1964 #9773322, 1965-71 #481030, 1972-75 #490766/#527503 which has the baffle and a NOTE: WHEN USING ON SOME 1973 EARLY JOBS DO NOT DISCARD EXISTING BOLTED ON TYPE OIL BAFFLE, AS THIS RETAINS THE OIL LEVEL TUBE /SUP #485339. I suspect the 2 different part numbers are for the rear oil pan seal type used as they changed, not the overall pan.

Also show Pan #1525745 - 1976 350 OR 400 PONT ENG — 1ST
TYPE Ran #1527503 - 1976 350 OR 400 PONT — 2ND TYPE —
HAS 5 HOLES IN FLANGE FOR REAR SEAL.

Dipstick Part #
1964 - two V8 dipsticks. The 4 Qt. #9773411 and the 5 Qt. #9777125. A/C did not affect the choice of dipstick. 326 Tempests, 2 bbl & 4 bbl 389 big cars were supposed to get the 4 Qt. Reading. The big car tripower 389 & all 421 equipped big cars plus all GTOs were supposed to get the 5 Qt. Reading. Due to a production error some very early GTO's got the 4 Qt. Reading.
1965 - #9777125
1966 - 1967 #9777951 - ALL 8CYL-EXC. AIR CONDITIONING
1967 #9789240 - ALL 8 CYL - WITH A/C
1968 - 1976 - #9793342 - Overall Length 19 3/4" - ALL 8CYL-EXC. AIR CONDITIONING
1968 - 1976 - #9793341 Overall Length 31 1/4"- ALL 8 CYL - WITH A/C, EXC. 1970 RA3 w/AC & 1971 455 HO w/AC
1971 - #483766 Overall Length 32 1/4" - A-body 455 HO w/AC

Upper Engine Dipstick Tube:
1967-1973 & 1974 455's - #9795830 - ALL 8 CYL - STRAIGHT 9-1/8" LONG /SUP 523707
A/C upper dipstick tubes have several part numbers over the various years.

Here are the pics taken by geeteeohguy comparing the 2 dipsticks:

Office ruler Rectangle Wood Font Line
Rectangle Wood Font Beige Hardwood
Wood Ruler Wood stain Flooring Office ruler
 
1 - 14 of 14 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top