RE compressing results

daniel mossey · Jun 27th, 2018, 20:18

Hi there before I was going to spend some money on various parts so I decided to do a compression test on the t5.
First test was cold and no wot results were cyl 1 151 cyl 2 140 cyl 3 142 cyl4 142 cyl5 142.
The next comp test was done hot and wot and the results were exactly the same.
The battery was dying which can affect the results so as I went along cylinders the results maybe could of been better. So bearing that in mind I retested cyl 1 which went down to 145 on a low battery.
Are these figures bad strange or ok?
The pcv needs to be done and I don't burn or smell oil being burnt but the levels need topping up now and again the spark plug condition is ok.
The car pulls very well and starts on the button.
Should I expect better results. The mileage is151000 and its 1997 v70 r .
Any ideas?
Regards
Dan

Dippydog · Jun 27th, 2018, 20:43

Compression test should be done on hot engine[normal temp] with wot and a fully charged battery.Disable both ignition and fuel systems before testing.haynes give compression figers of 11 to 13 bar for a turbo motor or 13 to 15 for n/a motors[don't know what those bar figures equate to in p.s.i.]as well as outright compression figure you're also looking for a fairly even reading across the cylinders.Again Haynes state not more than a 2 bar difference highest to lowest.If your figures are lower than stated put a little oil into cylinder to be tested and see if this raises the compression figure.

daniel mossey · Jun 27th, 2018, 21:13

Hi yes the 2 comp test was hot ant wot. I'll put in some oil and see if there's any change. The battery isn't fab after a few minutes if cranking 152 psi equates 10.48 bar

C70 98 · Jun 28th, 2018, 07:04

The specifications for a turbo Volvo is 156-185psi, but I believe it's better to have consistency in the readings than to be absolutely within the specification. I tried mine yesterday and had 160 on the lowest (2) and the others 170-180, not sure if I should worry really, but seeing as it builds pressure with a brand new PCV, I think I do need to worry.

DunkinBiskits · Jun 28th, 2018, 10:46

those numbers are a bit low. has someone used a non OE head gasket?

id expect atleast 165 or above

960kg · Jun 28th, 2018, 11:08

Most say do the test when hot But how hot??

It doesn`t matter one little bit what the temp. of the engine is as the compression's are all relative.

If it mattered about the temp. then why do some say put oil in the cylinders as that then makes a mockery of the test when hot?

Use of oil is handy when cold as it will boost the compression`s.

Whatever the temp. of the engine use a reliable compression tester not a cheap inaccurate one and so long as the pressure`s are all within 29psi of one another all is ok.......

daniel mossey · Jun 28th, 2018, 11:19

Head is on original gasket. Pcv is blocked whether this makes a difference I'm not sure.

daniel mossey · Jun 28th, 2018, 12:03

Ok did a final test just now. Hot engine and throttle open. No change on compression but when I put oil don the chambers they shot up to above 180 psi.
Is this a positive for worn rings or just a reaction to oil?
If it a worn ring conclusion its for me to decide to continue to invest as head work costs may not be on the cards. The reality it's a 21 year old car as good it is etc common sense must kick in. On the other hand it may last a long time...
Dan

C70 98 · Jun 28th, 2018, 15:39

Quote:

Originally Posted by Dippydog

haynes give compression figers of 11 to 13 bar for a turbo moto
Again Haynes state not more than a 2 bar difference highest to lowest.

Quote:

Originally Posted by 960kg

so long as the pressure`s are all within 29psi of one another all is ok.......

A variation within the specified 156-185psi or 11-13bar is acceptable in other words? That would be great news for me.

Quote:

Originally Posted by daniel mossey

Head is on original gasket. Pcv is blocked whether this makes a difference I'm not sure.

A clogged pcv gives the same effect as blow-by, and usually the oil is seeping out at the filler cap and oil filter, not enough to make a puddle under the car or burn off and smell, but enough to have to top up now and then.
At least it does on mine.

Dippydog · Jun 28th, 2018, 20:16

Usually if putting oil into the cylinders raises compression it points to worn/stuck piston rings,worn bores or both hence the reason for disabling the fuel system to stop "bore wash"/damage to the cat.I know nothing of the PCV system on these so don't know what effect a blocked one would have on the readings.However before condemning the engine does it use/burn oil?Is it lacking in power?Or have other engine maladies?

Jun 27th, 2018, 20:18	#1
daniel mossey Senior Member Last Online: May 1st, 2022 11:06 Join Date: Apr 2006 Location: WALTHAM ABBEY	RE compressing results Hi there before I was going to spend some money on various parts so I decided to do a compression test on the t5. First test was cold and no wot results were cyl 1 151 cyl 2 140 cyl 3 142 cyl4 142 cyl5 142. The next comp test was done hot and wot and the results were exactly the same. The battery was dying which can affect the results so as I went along cylinders the results maybe could of been better. So bearing that in mind I retested cyl 1 which went down to 145 on a low battery. Are these figures bad strange or ok? The pcv needs to be done and I don't burn or smell oil being burnt but the levels need topping up now and again the spark plug condition is ok. The car pulls very well and starts on the button. Should I expect better results. The mileage is151000 and its 1997 v70 r . Any ideas? Regards Dan

Jun 27th, 2018, 21:13	#3
daniel mossey Senior Member Last Online: May 1st, 2022 11:06 Join Date: Apr 2006 Location: WALTHAM ABBEY	Hi yes the 2 comp test was hot ant wot. I'll put in some oil and see if there's any change. The battery isn't fab after a few minutes if cranking 152 psi equates 10.48 bar Last edited by daniel mossey; Jun 27th, 2018 at 21:17.

Jun 28th, 2018, 10:46	#5
DunkinBiskits Master Member Last Online: Jan 1st, 2024 13:30 Join Date: Nov 2016 Location: Merseyside	those numbers are a bit low. has someone used a non OE head gasket? id expect atleast 165 or above __________________ https://www.facebook.com/VolvoComposites/ Horsepower is how fast you hit the wall Torque is how far you take the wall with you

Jun 28th, 2018, 11:08	#6
960kg Premier Member Last Online: Dec 28th, 2022 12:25 Join Date: Jun 2009 Location: Mercville	Most say do the test when hot But how hot?? It doesn`t matter one little bit what the temp. of the engine is as the compression's are all relative. If it mattered about the temp. then why do some say put oil in the cylinders as that then makes a mockery of the test when hot? Use of oil is handy when cold as it will boost the compression`s. Whatever the temp. of the engine use a reliable compression tester not a cheap inaccurate one and so long as the pressure`s are all within 29psi of one another all is ok....... __________________ Mercedes C320CDI Sport Estate 3 litre V6 7 Gear Auto Remap 290bhp 628Nm torque @ 1600revs 45.1mpg

Jun 27th, 2018, 20:43	#2
Dippydog Premier Member Last Online: Apr 25th, 2024 17:55 Join Date: Jun 2016 Location: S****horpe	Compression test should be done on hot engine[normal temp] with wot and a fully charged battery.Disable both ignition and fuel systems before testing.haynes give compression figers of 11 to 13 bar for a turbo motor or 13 to 15 for n/a motors[don't know what those bar figures equate to in p.s.i.]as well as outright compression figure you're also looking for a fairly even reading across the cylinders.Again Haynes state not more than a 2 bar difference highest to lowest.If your figures are lower than stated put a little oil into cylinder to be tested and see if this raises the compression figure.

Jun 28th, 2018, 07:04	#4
C70 98 Member Last Online: Jul 20th, 2021 20:51 Join Date: Aug 2013 Location: Middle part of Volvo country	The specifications for a turbo Volvo is 156-185psi, but I believe it's better to have consistency in the readings than to be absolutely within the specification. I tried mine yesterday and had 160 on the lowest (2) and the others 170-180, not sure if I should worry really, but seeing as it builds pressure with a brand new PCV, I think I do need to worry.

Jun 28th, 2018, 11:19	#7
daniel mossey Senior Member Last Online: May 1st, 2022 11:06 Join Date: Apr 2006 Location: WALTHAM ABBEY	Head is on original gasket. Pcv is blocked whether this makes a difference I'm not sure.

Jun 28th, 2018, 12:03	#8
daniel mossey Senior Member Last Online: May 1st, 2022 11:06 Join Date: Apr 2006 Location: WALTHAM ABBEY	Ok did a final test just now. Hot engine and throttle open. No change on compression but when I put oil don the chambers they shot up to above 180 psi. Is this a positive for worn rings or just a reaction to oil? If it a worn ring conclusion its for me to decide to continue to invest as head work costs may not be on the cards. The reality it's a 21 year old car as good it is etc common sense must kick in. On the other hand it may last a long time... Dan

Jun 28th, 2018, 20:16	#10
Dippydog Premier Member Last Online: Apr 25th, 2024 17:55 Join Date: Jun 2016 Location: S****horpe	Usually if putting oil into the cylinders raises compression it points to worn/stuck piston rings,worn bores or both hence the reason for disabling the fuel system to stop "bore wash"/damage to the cat.I know nothing of the PCV system on these so don't know what effect a blocked one would have on the readings.However before condemning the engine does it use/burn oil?Is it lacking in power?Or have other engine maladies?

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