Thread: 300TDI very very high compression!!!

sounds like about par for a tdi 300 that wants a little bit of maintenancy type loving.

Its not common for the tdi to leak coolant from the head gasket to the outside world, thats usually the job of the P gasket, water pump, thermostat housing gasket, the vactuator, the heater hoses, the heater hose transfer pipe and the thermostat bypass pipe fittings.

if you can confirm that it is definately leaking from the head its only a bout a days work to do an easy gasket change.

Yes, I confirm 100% that coolant is leaking from the head to the outside world.
So yes, if it's the only problem, I will be very happy.
I want to be sure that the cylinder compression is good so i want to try a good compression test. My tester only go into the heater plug.
So, can you tell me exactly how to do it ?

theres only 2 compression checks you can do on a diesel.

hot and cold.

before you start ensure you have a very good cranking battery thats fully charged or hook up a set of jumper cables to another vehicle that has its engine running at high idle.

for cold.

remove the wire that goes to the solenoid on the fuel injector pump, this, in theory stops all fuel flow to the injectors. As a backup crack each injector line union at the injector by about 1/2 to a full turn.

remove all your glow plugs

install your compression tester to a cylinder and crank the engine on the key. Count the number of compression cycles (I use 6-10) and read the pressure on the gauge, record it.

move the compression tester and crank the engine for the same number of compression cycles, record the pressure and then do the rest of the cylinders

The hot test is the same but you do it on a warmed up engine. it should hit the same pressures on 2-3 less compression cycles or hit about 20% more pressure on the same number of cycles as the cold test.


Something else thats worth doing while you have the glow plugs out is the leakdown test, this is done by blowing air into the cylinder through the glow plug hole with the piston at TDC on the compression/power stroke if you get air coming out the inlet your inlet valve is leaking, if it comes out the exhuast the exhaust valve leaks, excessively from the crank case ventilator and its the rings and out the cooling system and youve done a head gasket.


best of luck

Ok, that sound good. I will do all those test tomorrow and let you know what come out.

Thank's a lot Dave.

Back from the day!
So, we did the compression test like you told us.
And..... it work !!!! I have 410 to 420 in each cylinder.
what a relief!!!!
I will need to change the head gasket but that's it.
I was so happy to see the result on the the gauge.

Now, I can keep working on upgrading the truck for expedition

Thank you so much for all your help and a special thanks to you Dave !!!

Here a little picture of the truck!

Thank's again and I will post most picture of the process of the building of the truck from beggining soon, into another thread!

I wish you a very good day.

Cheers,

Matthieu

My Defender

Originally Posted by Matthieu

Back from the day!
So, we did the compression test like you told us.
And..... it work !!!! I have 410 to 420 in each cylinder.
what a relief!!!!
I will need to change the head gasket but that's it.
I was so happy to see the result on the the gauge.

Now, I can keep working on upgrading the truck for expedition

Thank you so much for all your help and a special thanks to you Dave !!!

Here a little picture of the truck!

Thank's again and I will post most picture of the process of the building of the truck from beggining soon, into another thread!

I wish you a very good day.

Cheers,

Matthieu

Matthieu -
This is why I suggested that you post either here or on the landrovernet.com websites when I read your post on the SA 4X4 Community site!

I've learned that these two sites have far more technically experienced members, capable of providing accurate and helpful support!

Bon voyage!

Thank's a lot for bringing me here and the good advice

Merci

Have a great day

Matthieu