3.10.
Connect the coupling on the gauge to the hose. Ensure the coupling is fully engaged.
3.11.
Crank the engine for at least five compression strokes, or until the pressure reading on the gauge stops rising.
3.12.
Record the compression reading, then push the side release valve to relieve the pressure.
3.13.
Repeat the test and record the reading. Relieve the pressure and remove the hose and adaptor from the spark plug well.
3.14.
Repeat for the remainder of the cylinders.
3.15.
You may also connect one of the Push On Connectors straight to the gauge coupling to aid quick installation. Select either the straight
or angled stem for easiest access.
4. TEST RESULTS
4.1. GAUGE READINGS
4.2.
On a normal cylinder, the gauge needle should travel up the scale on each compression stroke until it reaches peak value. All cylinders
should indicate a pressure that is within the vehicle manufacturer’s specifications; the reading should not vary by more than 10%
from cylinder to cylinder.
4.3.
If the gauge needle does not travel up the scale or if it remains at the same value for several strokes and then starts to climb, the
problem could be a valve sticking.
4.4.
If the compression reading is considerably higher than the vehicle manufacturer’s specification, the problem may be carbon build-up in
the cylinder. It may also indicate that either the piston, or the cylinder head, has been modified.
4.5.
If a reading on two adjacent cylinders is 20psi (or more) lower than the other cylinders, the problem may be a cracked cylinder head or
defective main gasket. Under these conditions, both coolant and oil may be found in both cylinders.
4.6.
If the readings are low, or vary widely between cylinders, pour 5ml of SAE 30 oil into each cylinder and retest them. If the
readings increase considerably, the problem may be poorly seated, or worn, piston rings. If the readings remain about the same, the
valves and/or associated components may be the problem. A burnt or damaged piston may also cause the same results.
5. COMPLETION OF TESTS
c
5.1.
Clean, re-gap and reinstall the spark plugs in
the same order in which they were removed, or
install new spark plugs.
5.2.
Reconnect each spark plug lead to the plug it was
connected to prior to removal.
5.3.
Return the throttle plates to the closed position.
IMPORTANT: After test, failure to return the
throttle plates to the closed position before
starting the engine can cause serious damage to
the engine.
5.4.
Reconnect the ignition system wiring disconnected in
paragraph 3.8.
Sealey Group, Kempson Way, Suffolk Business Park, Bury St Edmunds, Suffolk. IP32 7AR
01284 757500
01284 703534
www.sealey.co.uk
Note
: It is our policy to continually improve products and as such we reserve the right to alter data, specifications and component parts without prior
notice.
Important
: No Liability is accepted for incorrect use of this product.
Warranty
: Guarantee is 12 months from purchase date, proof of which is required for any claim.
ENVIRONMENT PROTECTION
Recycle unwanted materials instead of disposing of them as waste. All tools, accessories and packaging should be sorted, taken to
a recycling centre and disposed of in a manner which is compatible with the environment. When the product becomes completely
unserviceable and requires disposal, drain any fluids (if applicable) into approved containers and dispose of the product and fluids
according to local regulations.
CT995.V4 Issue: 1 22/10/18
Original Language Version
© Jack Sealey Limited
