High Mileage Compression Test

[Andaloons]

I did a compression test this morning. I'm at 155k miles.

sprocket|180|185|185|160

If anyone else has done a compression test with high mileage let's see your results!

Thanks!!

[coolvdub]

At 300k mine were 160-165 not bad if you ask me. Will be at 400k in a couple months, maybe I will check it again, maybe not.

[DTM1.8t]

Holy Crap,

I have 3 jettas in my family and they dont add up to that together man


props

you worn a hole through your drivers seat yet or what...??

[codergfx]

140 130 125 140 yea gf piston rings 140k miles

Friends motor 178k
155 155 150 160

[builtvw]

150k

180/180/180/175

[urluzn2]

Mine at 150k
189|189|191|185

[Camride]

I don't remember the exact numbers but I just did mine a few months ago, so it would have been between 145k-150k miles and all 4 were between 190-200psi. I was pretty stoked when I saw that, especially because I had just busted my timing belt (long story).

[RobbieRolex]

Mine at 50k

Cylinder 1 = 11.2 bar / 162psi
Cylinder 2 = 10.9 bar / 158 psi
Cylinder 3 = 11.6 bar / 168 psi
Cylinder 4 = 11.8 bar / 171 psi

[Budsdubbin]

I'm kind of lost here some of you are getting pretty high results. From what I can remember spec should be around 160-140psi. When checking your compression how many times did you let the pressure build or turn over the engine? Its supposed to be 3 or 4 turns.

[Camride]

I'm kind of lost here some of you are getting pretty high results. From what I can remember spec should be around 160-140psi. When checking your compression how many times did you let the pressure build or turn over the engine? Its supposed to be 3 or 4 turns.

I did 4 turns for each. I thought the numbers were high, but it was with a brand new compression tester. I may try it again when I change my plugs soon.

[RobbieRolex]

4 iirc, but i was always advised it not the reading that matters (well unless it super low) moreover the consistency between cyclinders, some devices read high and some low, but they should consistantly replicate the result so you can spot a cyclinder reading low.

[Andaloons]

I'm kind of lost here some of you are getting pretty high results. From what I can remember spec should be around 160-140psi. When checking your compression how many times did you let the pressure build or turn over the engine? Its supposed to be 3 or 4 turns.

Yeah, I turned mine over 4 times for each cylinder.

Bentley says:
New Cylinders 145-203psi
Wear Limit 102psi
Max Difference Between Cylinders 44psi

[builtvw]

I'm kind of lost here some of you are getting pretty high results. From what I can remember spec should be around 160-140psi. When checking your compression how many times did you let the pressure build or turn over the engine? Its supposed to be 3 or 4 turns.

yah i did 4

[4ringkings]

i have to check mine

[groggory]

175 | 145 | 180 | 180

Motor was pretty much rebuilt ~45k miles ago

[The Mailman]

at 93k miles, all 4 of mine were right around 185. I've put 10k on it since then, but since I drive 30k a year, I'll check it again in 6 months or so and see how the wear is doing (hopefully none at all)

[Mindfault]

you guys are checking with the throttle body open?

[Vegeta Gti]

50k or so on BT,stock pistons, four years of hell

183 all across

[jettamk401]

My MK4 has 126k, was getting poor gas mileage. Did compression check with engine hot. 240psi across all cylinders. Trying to come up with why??? Any ideas??

[All_Euro]

My MK4 has 126k, was getting poor gas mileage. Did compression check with engine hot. 240psi across all cylinders. Trying to come up with why??? Any ideas??

That's high man. OEM range is 145 psi - 203 psi. You may have carbon build-up on your pistons. Poor fuel mileage can be caused by a lot of things but a good place to start is by checking for exhaust and intake/vacume leaks.

[All_Euro]

I just checked my compression today @ 187,000 kms (116,000 miles)...

• Cyl #1 - 145 psi
• Cyl #2 - 150 psi
• Cyl #3 - 150 psi
• Cyl #4 - 150 psi

Within spec but seems low

[Gulfstream]

AGU head has 18k miles and bottom bored/stroked to 2008cc:

196 - 196 - 196 - 190 psi

[rains]

you guys are checking with the throttle body open?

Does this make a difference? Also, should compression be checked on a warm or cold motor?

[AmIdYfReAk]

Does this make a difference? Also, should compression be checked on a warm or cold motor?

All tests should be with the TB open ( you're not trying to test Vacuum are you? ), IMO the tests should be done on a Warm engine.

Cold compression Vs warm compression tells the kinda wear on the engine as well.

Btw, i usually stick a screwdriver in the throttle body while i test....

[rains]

All tests should be with the TB open ( you're not trying to test Vacuum are you? ), IMO the tests should be done on a Warm engine

Never knew this! But, when you put it that way, it makes sense

I only checked my compression once, but I did it on a cold engine and I didn't have the TB open. All I did was unplug injectors and coils ... I should give it a go again but do it properly.

Thanks, eh

[All_Euro]

- Engine temp should be min 30*C / 86*F
- Fully depress pedal & crank at least 5 revolutions

[MÄDDNESSS]

AWP. 152K miles.
cold-160, 155, 150, 160.
warm- 180, 170, 165, 175.

[Shad]

I just checked my compression today @ 187,000 kms (116,000 miles)...

• Cyl #1 - 145 psi
• Cyl #2 - 150 psi
• Cyl #3 - 150 psi
• Cyl #4 - 150 psi

Within spec but seems low

Mine with 109.000km (68.000mi) has 133/136/136/129 PSI. A bit low but runs fine. Of course that daily use on heavy stop and go traffic don't help.

[Rod Ratio]

Mine were 180's all acrossed the board at over 200k

[RodgertheRabit II]

Finally checked mine. Satisfied for a random Donor block with at least 140-160K (on the motor, not the car ).

165 - 153 - 159 - 163.

[RodgertheRabit II]

Finally checked mine. Satisfied for a random Donor block with at least 140-160K (on the motor, not the car ).

Cyl 1 = 165
Cyl 2 = 153
Cyl 3 = 159
Cyl 4 = 163

[ajshoe]

I've checked over 40 1.8 T for compression - majority all over 100K. Have checked several over 200K. My findings are 99% engines that are below 140 Psi or ones that have odd readings are valve related. Only seen a couple low readings from ring wear (the few I've seen were because the owner drove with the engine running rough (coolant entering oil). I have not seen one head gasket leak or head gasket problem on any of these repairs.
I currently drive a passat with 210K and compression readings @ 180 (all within 5 psi). This is the original motor - not rebuilt. It did have the sludge problem - fixed at 190K. I believe these engines can easily go 300K+ miles if properly taken care of. Use synthetic 0w40 oil and oversized oil filters every 5000 miles.