Hello guys!
I cleaned the egr valve, egr throttle body and intake manifold.
It was a pain in the a**, but I did it.
It didn't solve my mpg and acceleration problem. The only benefit is a more silent engine and overall ''good working engine'' feeling.
The egr valve vas unexpectedly clean after 101.000 km. The egr cooler was 1/2 clogged. The throttle body was ok. The intake manifold had about 0,5 cm thick layer of soot on the inside walls. I changed all the gaskets (before egr, egr body to egr cooler, egr cooler to intake manifold). I didn't change the intake manifold gasket because the one I got from the parts dealer was thinner and the original one was in great shape.
For the cleaning I used a wire brush, a brush (for paint, with animal hair), throttle body cleaner spray, egr cleaner spray, brake cleaner spray, oven cleaner foam spray and gasoline. I got the best results with the brake cleaner spray.
While taking off the egr cooler I changed the coolant temperature sensor. I bought an aftermarket one made by Topran Germany. I unscrewed the original sensor and screwed by hand first the new one and after I used a spanner to torque it (I think this is the name). After 3-4 turns with the spanner I heard a creaking sound.
The thermostat housing broke. I had to change it. It costs a sh*t load of money. Pics attached.
My advice is to use only hyundai oem parts. I guess the Topran sensor maybe was thicker with 0,1 mm or something like that (unnoticeable with eye) and it cracked the crappy part.
I finally resolved the MPG problem by using Liquid Moly intake cleaner diesel code 5168. I sprayed the can in the air intake hose, after the maf sensor in short 2-3 sec burst while maintaining an average 2000 rpm. When I sprayed the solution the rpm would rise up to 3000 rpm and after a few seconds it dropped back to 2000 rpm.
The procedure took about 10 min. The effect was instant. Now the fuel consumption dropped from about 8-9 l/100 km to 5-6 l/100 km urban driving.
The acceleration is more responsive.
I guess, in conclusion, that in my case I had big deposits on the intake/exhaust valves and probably on piston heads and injectors. By removing this soot deposits I think the compression is better now and I stopped loosing power (more fuel is needed if you have bad compression).
I will attach some photos and I hope they might be useful.
Thank you all for your help!
All pipes protected with pastic bags to prevent contamination.
In the picture you can see the base of the egr valve connected to the pipe that comes from the exhaust gallery. Notice the metal gasket (all replaced).
Intake manifold after throttle body removal.
Intake manifold after throttle body removal.
Intake manifold after throttle body removal.
Intake manifold after throttle body removal.
Intake manifold after throttle body removal.
Throttle body.
Throttle body - closer view.
Air heater on throttle body.
Air heater on throttle body - closer view.
New thermostat housing with part code.
New thermostat housing Hyundai OEM.
Old thermostat housing with a crack around the cooling temperature sensor.
Old thermostat housing with a crack around the cooling temperature sensor - closer view.
