Thursday, June 24, 2010

Coolant Change, Engine and Radiator Flushing

Replaced the 7 years old original coolant. Supposed to use only Revkogel 2000 or Glysantin G33 as specified by Peugeot, but used Shell OAT coolant instead, since they are the same technology.

Old coolant must be collected in a container and disposed properly. To drain the old coolant, the expansion chamber cap was opened and the bottom radiator hose was disconnected.


This is how 7 years old coolant looks like. Brown just like mud water. New coolant is orange and transparent.

The thermostat and top radiator hose was removed prior to flushing the engine cooling circuit.

The thermostat.

The thermostat. Scale had deposited onto the black rubber seal. It was removed by soaking in vinegar and gently picking them off.

The top and bottom radiator hose was removed to flush the radiator separately from the engine.

Next was engine flushing. Water was fed into the expansion chamber...

...and water comes out from the other ends.

The cleaned thermostat and rubber seal put back.

Shell Coolguard OAT works well. I used 1 liter coolant with 2 liters of water. 6 liters of solution was required.

Bleed point for removing air.

Bleed point for removing air.

Sunday, June 13, 2010

AL4 Hydraulic Valve Block

After finding the AL4 transmission rebuild manual a few days ago, I had the confidence to dismantle the AL4 hydraulic valve block. The gear change has not been smooth and I've suspected sticky valves all along. The transmission oil is almost 7 years old and clocked 77,000km. Since I planned to do a transmission oil change anyway, I decided to clean the valve block before putting in new oil. Also cleaned was the oil pressure sensor, located just beneath the block.

WARNING! Don't try doing this on your own if you don't know what you are supposed to do and not familiar with hydraulic valves. Doing this wrong can permanently kill the transmission.



There are two square-shaped strong magnets at the bottom of the lid, to collect any metal bits.

Rust where there isn't supposed to be any. This is a sure sign of water getting into the transmission. In this tropical rainy weather, it is a good idea to change the oil frequently to get rid of any water.


This block is still using the old/obsolete type of solenoid valves part 2574.10. These should be replaced with the newer Borg Warner valves part 2574.16, which will require an ECU software update. But unfortunately there's no Peugeot service centre in town that can do this, so I'm stuck with the old valves for the time being. Anyway the valves are still working, so I'm not too bothered to change them yet.


These are the sequence electrovalves, EVS. I've switched EVS5 (reverse gear) with EVS2 (for 2nd gear and 4th gear) because shifting from 1st into 2nd gear is intermittently not smooth and I suspect EVS2 not working properly.






The webbing can be wiped clean using lint-free cloth. I used cleanroom wipes since I have lots of it. I also took out all the EVS and sequence valves to clean them and drain out the old oil. The main block and auxiliary block was separated to allow all the old oil to come out and allow cleaning of the webbing and plates.




The result of the cleaning and new oil is a smoother gear change.

Related AL4 Posts

Saturday, June 5, 2010

Throttle Body

I had nothing better to do, so I decided to open the throttle body. The engine has not been idling smoothly, so it was a good idea to open up the throttle body to check.

After opening it up, I found a layer of sticky carbon buildup around the idle air control (IAC) valve, the air bypass passage and the throttle. No wonder the engine was not idling smoothly. Anyway, a good clean with a toothbrush, cloth and some petrol helped remove most of the carbon.

The throttle body; throttle at the bottom, air bypass passage at the top, idle air control valve at the top right and throttle position sensor (TPS) at the bottom right.

The idle air control valve is cleaned. No more carbon on the valve.


Carbon removed from the air bypass passage.



A peek inside the air intake.