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djkeev
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Joined: September 30, 2007
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Location: Reading Pennsylvania
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?Waldo?
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Joined: February 22, 2006
Posts: 9752
Location: Where?
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 Posted: Sun Apr 17, 2022 2:31 pm Post subject: Re: Leak of coolant, then engine quit: noobie trouble |
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I don't care at all if anyone disagrees with me, nor do I care at all if someone wastes their time doing a cold compression test, nor if they waste even more of their time/money making bad decisions based on a misleading (useless) cold compression test.
A few years ago I purchased a westy for cheap after a local mechanic did a cold compression check and told the owner they needed a new engine. When I rechecked the compression with the engine hot and the lifters all pumped up it was totally within spec! |
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Abscate
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Joined: October 05, 2014
Posts: 22633
Location: NYC/Upstate/ROW
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| Posted: Sun Apr 17, 2022 2:55 pm Post subject: Re: Leak of coolant, then engine quit: noobie trouble |
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A cold compression test is useful but many beginners haven’t learned how to interpret that data. A hot test is better, certainly.
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?Waldo?
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Joined: February 22, 2006
Posts: 9752
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| Posted: Sun Apr 17, 2022 3:17 pm Post subject: Re: Leak of coolant, then engine quit: noobie trouble |
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| deadaheadub wrote: |
The compression numbers are in:
1- 120
2- 110
3- 70
4- 80... |
The OP's numbers are at-best misleading. They look low, but the engine compression could absolutely be within spec if the test is done correctly. I believe the compression is high enough that the engine would run, so you might find that info worthwhile, but there are easier ways to arrive at that conclusion. The results certainly aren't definitive for determining whether or not heads need to be pulled, etc... |
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oceanair
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Joined: June 09, 2013
Posts: 720
Location: Victoria, BC
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| Posted: Sun Apr 17, 2022 4:11 pm Post subject: Re: Leak of coolant, then engine quit: noobie trouble |
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| Quote: |
| The OP's numbers are at-best misleading. They look low, but the engine compression could absolutely be within spec if the test is done correctly. I believe the compression is high enough that the engine would run, so you might find that info worthwhile, but there are easier ways to arrive at that conclusion. The results certainly aren't definitive for determining whether or not heads need to be pulled, etc... |
I absolutely agree -- 70 and 80 cold, will only be higher hot and would certainly run. Even if someone disagrees that it would go up hot, it would start cold. 70 and 80 Psi is still a lot of compression.
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84 Vanagon Pop Top Conversion from Tin Top, 1970 Ghia - all sweet rides! Love em!
Previous: Green 72 Tin Top, White 72 Westy, Blue 64 Beetle, Yellow 71 Squareback, 2014 Jetta TDI Wagon - wish I could have them all back! |
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djkeev
Samba Moderator
Joined: September 30, 2007
Posts: 32562
Location: Reading Pennsylvania
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| Posted: Sun Apr 17, 2022 6:05 pm Post subject: Re: Leak of coolant, then engine quit: noobie trouble |
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| oceanair wrote: |
| Quote: |
| The OP's numbers are at-best misleading. They look low, but the engine compression could absolutely be within spec if the test is done correctly. I believe the compression is high enough that the engine would run, so you might find that info worthwhile, but there are easier ways to arrive at that conclusion. The results certainly aren't definitive for determining whether or not heads need to be pulled, etc... |
I absolutely agree -- 70 and 80 cold, will only be higher hot and would certainly run. Even if someone disagrees that it would go up hot, it would start cold. 70 and 80 Psi is still a lot of compression. |
Never said it wouldn't get better hot.
They most assuredly will.
But are you a dealer trying to show a healthy engine to get out of fixing it or a shop trying to show an engine in need of repair?
Again, it is like checking for a coolant leak on a hot engine, it just doesn't leak....... until the engine goes stone cold.
As a rule of thumb, you are looking for consistency in a neighborhood. Not an exact "must have" number.
If cold numbers are horrible, warm it up and retest.
Dave
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http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537
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?Waldo?
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Joined: February 22, 2006
Posts: 9752
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| Posted: Mon Apr 18, 2022 8:41 am Post subject: Re: Leak of coolant, then engine quit: noobie trouble |
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| djkeev wrote: |
| But are you a dealer trying to show a healthy engine to get out of fixing it or a shop trying to show an engine in need of repair? |
I'm neither one and do not have either bias. I am someone with experience and understanding who is helpfully sharing that experience and understanding from the bias of wanting to help other owners make informed decisions about how to maintain/repair their vehicle in the easiest, most economical, and most effective ways. The cold compression check that the OP did does not fit with that and taking any action based on those potentially significantly misleading results is unwise. |
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oceanair
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Joined: June 09, 2013
Posts: 720
Location: Victoria, BC
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| Posted: Mon Apr 18, 2022 9:13 am Post subject: Re: Leak of coolant, then engine quit: noobie trouble |
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Either way -- a compression of 70 and 80 with 120 on the other side should not stop an engine from starting, so the starting issue is elsewhere, for sure.
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84 Vanagon Pop Top Conversion from Tin Top, 1970 Ghia - all sweet rides! Love em!
Previous: Green 72 Tin Top, White 72 Westy, Blue 64 Beetle, Yellow 71 Squareback, 2014 Jetta TDI Wagon - wish I could have them all back! |
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deadaheadub
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Joined: April 18, 2004
Posts: 787
Location: New Mexico
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| Posted: Mon Apr 18, 2022 9:13 am Post subject: Re: Leak of coolant, then engine quit: noobie trouble |
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Thanks for the discussion of these facts. I can use all the information I can get on these issues to build up my personal knowledge base.
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Grateful daily,
Ryan
______________________________________
Past loves: '65 Bug, '70 Westy poptop, '64 Squareback project, '76 Westy tintop "Loose Lucy", '76 Westy tintop "Sharee"
Current:'84 Westy poptop "Ramblin' Rose- Rosie" w/ 2003 Subaru EJ25 conversion |
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?Waldo?
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Joined: February 22, 2006
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| Posted: Mon Apr 18, 2022 9:43 am Post subject: Re: Leak of coolant, then engine quit: noobie trouble |
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| What is the elevation where you are in New Mexico? |
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deadaheadub
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Joined: April 18, 2004
Posts: 787
Location: New Mexico
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| Posted: Mon Apr 18, 2022 10:01 am Post subject: Re: Leak of coolant, then engine quit: noobie trouble |
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| ?Waldo? wrote: |
| What is the elevation where you are in New Mexico? |
Around 6000'
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Grateful daily,
Ryan
______________________________________
Past loves: '65 Bug, '70 Westy poptop, '64 Squareback project, '76 Westy tintop "Loose Lucy", '76 Westy tintop "Sharee"
Current:'84 Westy poptop "Ramblin' Rose- Rosie" w/ 2003 Subaru EJ25 conversion |
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?Waldo?
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Joined: February 22, 2006
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| Posted: Mon Apr 18, 2022 10:24 am Post subject: Re: Leak of coolant, then engine quit: noobie trouble |
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So that altitude will reduce the compression pressure to about 83% of what it would be at sea level.
The minimum spec for the WBX engines is 116 psi. The minimum spec for compression with engine hot and the lifters properly pumped up at 6,000' of elevation is 96 psi (116 x 0.83 = 96). It is very possible (actually probable) that your compression is actually within spec. |
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deadaheadub
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Joined: April 18, 2004
Posts: 787
Location: New Mexico
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| Posted: Mon Apr 18, 2022 10:33 am Post subject: Re: Leak of coolant, then engine quit: noobie trouble |
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Thank you, ?Waldo?
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Grateful daily,
Ryan
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Past loves: '65 Bug, '70 Westy poptop, '64 Squareback project, '76 Westy tintop "Loose Lucy", '76 Westy tintop "Sharee"
Current:'84 Westy poptop "Ramblin' Rose- Rosie" w/ 2003 Subaru EJ25 conversion |
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djkeev
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Joined: September 30, 2007
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?Waldo?
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Joined: February 22, 2006
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| Posted: Tue Apr 19, 2022 6:33 am Post subject: Re: Leak of coolant, then engine quit: noobie trouble |
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| deadaheadub wrote: |
| ...I just wanted a little more clarification of how much "a few pumps" is. (I can get pretty "detailed".) Seems like "a few pumps" could fill up the holes. Does it matter, can you squirt in too much?... |
Yes, you can certainly squirt in too much. If you get close to or exceed the unswept volume of the combustion chamber, you will hydrolock the engine and bend connecting rods. That would take a significant amount on a gasoline engine, though. As an aside, oil should NEVER be added to the cylinders of a diesel engine. The combustion chamber volume is much smaller which greatly increases the chance of hydrolock and the higher compression can (will) ignite the oil and blow up the compression gauge.
Repeating the cold compression test with oil added is just a distraction and waste of time, though. Your compression is very likely within spec and is not what is preventing the engine from running. There is no point to wasting your time 'diagnosing' a non-issue. |
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deadaheadub
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Joined: April 18, 2004
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Location: New Mexico
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| Posted: Tue Apr 19, 2022 7:34 am Post subject: Re: Leak of coolant, then engine quit: noobie trouble |
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Thank you, Dave and Waldo
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Grateful daily,
Ryan
______________________________________
Past loves: '65 Bug, '70 Westy poptop, '64 Squareback project, '76 Westy tintop "Loose Lucy", '76 Westy tintop "Sharee"
Current:'84 Westy poptop "Ramblin' Rose- Rosie" w/ 2003 Subaru EJ25 conversion |
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deadaheadub
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Joined: April 18, 2004
Posts: 787
Location: New Mexico
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| Posted: Mon Dec 05, 2022 1:18 pm Post subject: Re: Leak of coolant, then engine quit: noobie trouble UPDATE |
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Finally took the plunge, and my mechanic finally got the time for my subie conversion.
I would have liked to keep it all VW, but I was so frustrated and tired of limping back home from a trip, or being towed home, and, not being skilled enough to fix the problems myself, having to wait months for a mechanic who was able to get it back on the road.
I really love the feel of the new powertrain. It runs down the road so smoothly. Love it. Much more confident taking long trips and knowing I've a good chance of making it home without major issues cropping up along the way.
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Grateful daily,
Ryan
______________________________________
Past loves: '65 Bug, '70 Westy poptop, '64 Squareback project, '76 Westy tintop "Loose Lucy", '76 Westy tintop "Sharee"
Current:'84 Westy poptop "Ramblin' Rose- Rosie" w/ 2003 Subaru EJ25 conversion |
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dobryan
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Joined: March 24, 2006
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Location: Brookeville, MD
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leecat
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Posts: 773
Location: Regina
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| Posted: Mon Dec 05, 2022 3:00 pm Post subject: Re: Leak of coolant, then engine quit: noobie trouble |
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| Thanks for coming back and updating! Super nice - congrats. |
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