Service Plans
Car Servicing
Car Diagnostics
Auto Electricians
Brakes
Pricing
Areas We ServiceOur service team is available 6 days a week
Book Your
Everything else tests the systems around the engine. A compression test measures the condition of the engine itself.
When a misfire will not go away and nothing electrical explains it, this is the test that tells you whether the problem is mechanical.
- 4.3 ★1,533 Google reviews
- 6 monthsor 6,000 km workmanship warranty
- Red SealQualified artisans, some ex-dealership
- 9 regions1,700+ suburbs, we come to you
Priced for your car
Tell us what the engine is doing and we come back to you with a price.
A compression test depends on the engine and how much has to come off to reach the plugs, so we quote it per car rather than printing a figure that would be wrong for most of them.
Coils and plugs do not fix a mechanical misfire
A cylinder with low compression misfires exactly like one with a dead coil, and it keeps misfiring after the coil, the plug and the injector have all been replaced. Our prices for the parts usually bought first:
Ignition coil replacementR952 to R1,102
Spark plugs replacementR952 to R2,173
Finding out which one it actually isQuoted for your car
When compression is the right test
Four patterns where the answer is mechanical rather than electrical.
A misfire that survived new coils, plugs and injectors
The classic case. When the electrical side has been replaced and the cylinder still misfires, the cylinder itself is the suspect. More on this.
Using oil, with blue smoke on start up or under load
Oil getting past the rings or the valve stem seals. Compression, and where needed a leak down, separates the two.
Down on power with no fault codes at all
Nothing electrical is wrong, which is itself informative. Lost compression costs power quietly and logs nothing.
It overheated badly and has never run right since
A warped head or a failed gasket shows up here immediately, often alongside a combustion gas test. More on this.
Not sure which one yours is?
Tell us what the car is doing, in your own words. A mechanic reads it and calls you back within the hour. You do not need to know what is wrong, that is what we are for.
Tell us what your car is doing
What people say after we have been out
Real jobs, real faults, at homes and offices.
What the test involves
✓
Every cylinder measured, not just the suspect oneThe comparison between cylinders is what matters. One low cylinder among healthy ones means something quite different from all of them being low.
✓
Readings taken at a consistent cranking speedA compression tester only gives comparable numbers under comparable conditions, which is why battery condition is checked first.
✓
Wet test where a cylinder reads lowA little oil into the cylinder separates worn rings from a valve or gasket problem, and it costs nothing to do.
✓
Results read against the manufacturer’s figuresBoth the absolute number and the spread across cylinders, because an engine can be within tolerance overall and still have one bad cylinder.
The kit that comes with the mechanic
A mobile mechanic is only as good as what is in the van.
Compression tester
Every cylinder measured at a consistent cranking speed, so the readings are comparable with each other and with the manufacturer’s figures.
Battery load tester
Checked first, because a weak battery cranks slowly and produces low readings on a perfectly healthy engine.
Autel and Launch scan tools
Misfire counters per cylinder read first, so the test confirms what the live data already pointed at.
Combustion gas test
Where a low cylinder sits next to a coolant problem, this establishes whether the head gasket is the link between them.
This is a measurement, not a repair
A compression test tells you the condition of the engine. If the numbers are bad, the work that follows is significant, and you will get that priced properly before anyone starts. If the numbers are good, you have ruled out the expensive possibility.
What you get for the money
A named fault, in writing, and a price to fix it
What has failed, why, and what the repair involves. If the repair is ours you get the quote before anything is touched, and the inspection is not charged twice.
Other inspections we do
Every one of these is a mechanic coming to you. See all 22.
Losing powerR952 to R1,104Limp mode, or it will not pull.Car shakingR952 to R1,104Under braking, at speed, or at idle.Plug-in diagnostic scanR952 to R1,104Every module read, not just the engine.Fuel pressure testR1,035 to R1,225Hard starting, cutting out under load.Speedometer not workingR952 to R1,104Dead, erratic, or reading wrong.Engine light onR952 to R1,104Steady, flashing, or on and off again.Dashboard warning lightsR952 to R1,104A light you do not recognise.EPC warning lightR952 to R1,104VW, Audi, Seat and Skoda.
Where we come out to
Nine regions and more than 1,700 suburbs. Check your suburb.
JohannesburgPretoria and TshwaneCape TownDurban and eThekwiniEkurhuleni and the East RandGqeberhaPolokwaneRustenburgEmalahleni
Questions we get asked
What does a compression test actually tell me?
Whether each cylinder is sealing properly. Low compression means the cylinder is losing pressure past the rings, the valves or the head gasket, and no amount of ignition or fuel work will fix that.
My misfire came back after new coils and plugs. Is this the next step?
Usually yes. When the electrical side has been replaced and the same cylinder still misfires, the cylinder itself becomes the most likely explanation, and this is the test that confirms or clears it.
What is a leak down test, and do I need one?
It is the follow up. Compression tells you a cylinder is losing pressure; a leak down test tells you where it is going, past the valves, the rings or the gasket. We do it when the compression figures point there.
How much does it cost?
Tell us what the engine is doing and where you are, and we will come back to you with a price for your car. A mechanic reads what you send and calls you back.
Engine Compression Test At Your Door
Tell us what it is doing and where you are. Price and a slot, no phone call.