I remember Scotty stating that diesel EGR valves lower the combustion chamber temperature by altering the ratio of fuel to air. So too much air means the engine runs too hot. I've got a Lexus 2AD-FHV engine that everyone says is prone to head gasket failure, and I don't wanna mess with it.
On the other hand, I clean out the EGR valve every couple of weeks and can see the amount of crud going into the engine. Apparently Lexus did such a good job with the DPNR (Diesel Particulate Nox Reduction) catalytic converter that it could still pass emmisions over here in the UK for the annual MOT check with the EGR removed.
So if I install a bigger radiator, put insulation tape on the wiring, remove the beauty covers - that sort of thing, can I compensate equally for the EGR heat reduction and how do you measure that sort of thing? Or am I playing with fire, and the engine is gonna blow up as soon as I get stuck in traffic?.
Thanks.
EGR valves lower the combustion chamber temperature by altering the ratio of fuel to air.
No. EGR does not change fuel/air ratio. It simply reduces the total amount of fuel AND air mixture.
Lexus 2AD-FHV engine that everyone says is prone to head gasket failure
If head gaskets are a weakness, then replace with a better aftermarket gasket.
am I playing with fire
Messing with your engine will likely result in reduced lifetime.
bigger radiator ... remove the beauty covers
Won't do anything. Coolant temp is set by the thermostat.
put insulation tape on the wiring,
{black}:idontknow:
can I compensate equally for the EGR heat reduction
so to clarify, you are asking if raising combustion temperature will make your head gasket last longer?
No.
So it's hearesay that Lexus made a crap head gasket on the 2AD-FHV engine. Personally I find it hard to believe.
So the whole point of this question is moot, then.
if you get all this carbon buildup in the engine, does that increase heat and lead to head gasket failure?
As far as I know, no. As your article explains, EGR decreases combustion temperature.
So what I want to do is remove the EGR because it dumps carbon into the combustion chamber
And where would the carbon come from?
So could you elaborate when you say it only reduces the fuel & air mixture?
In order to change the air/fuel mixture, you would need to add fuel or oxygen. EGR gasses have neither. They are "inert". They simply displace the normal mixture. It's the same as having a smaller cylinder.
Does that not lower the temperature in the combustion chamer?
Yes, it does.
if I remove the EGR will that lead to higher engine operating temperatures and lead to head gasket failure as well?.
It might slightly reduce its lifetime from localized heat. But as I said before, engine operating temp is regulated by the cooling system.
Just use a lower temperature thermostat, about $7.
Hi Doc,
So does that mean you're lowering the temperature below what it should be operating at?. My brain hurts. {black}:afraid:
Well I don't know if it will gain you anything. On the Detroit heavy truck engines made in the late 2000's we had trouble with rhe egr valves sticking. When the egr valve stuck the engine would blow huge amounts of black smoke and the engine would lose power. One solution to this was if you had a buddy it the shop you could ask him to test the egr valve. During the test when the valve was open you simple unplug it and leave it unllugged. The exhaust would smoke more because you just bypassed the emissions but no more egr worries.
Correction it was the Cummins not the Detroit.
Thanks @JimDoghouse. I'm a bit of a wimp as far as that goes because I'm afraid it might trip the engine code and put the car into limp mode. It would be the perfect answer though as it just shuts everything down and if the EGR valve is clean, it's shut.
There's a motorised valve that bolts onto the back of the valve that I think opens up whenever it needs to. The mechanical part of the valve itself is on a spring and the motorised valve just pushes it open.
Also we're having a bit of a fuel crisis atm here in the UK because a blonde orangutan for a prime ministed is sitting up in a tree somewhere scratching hit head wondering where it all went wrong, while his bimbo tree-hugger girlfriend bullies him from below and everyone in parliment about saving the planet. So 90% of fuel stations across the country are empty. Which makes taking chances on the road a bit too risky.
Hi @MountainManJoe, thanks for the reply.
I can't quote Scotty Kilmer because I can't remember the video he mentioned this in. But I was just being a prat when I was talking about the insulation tape and all that, because obviously I want a measurable, mechanical way of keeping the engine cool if I mess with it and it exceeds the operating temperature. So, difficult to describe because I'm not a mechanic, but the "overhead" capacity of heat the engine can deal with if you like.
So it's hearesay that Lexus made a crap head gasket on the 2AD-FHV engine. Personally I find it hard to believe. Far more likely that people arn't maintaining their cars / getting ripped off. But I appreciate that you're saying it will fail it it's rubbish.
So what I want to do is remove the EGR because it dumps carbon into the combustion chamber. So could you elaborate when you say it only reduces the fuel & air mixture? Does that not lower the temperature in the combustion chamer? As I said, I think that's what Scotty said, but I've also got these two articles here:
https://toyota-club.net/files/faq/13-01-01_faq_ad-engine_eng.htm
The first one says: "Since the specific heat capacity of both CO2 and water vapour is greater than that of oxygen, the gas temperatures within the engine cylinder during combustion is reduced. Also, because the exhaust gases absorb some of the heat generated during combustion, the maximum combustion temperature per engine cycle is also reduced."
And the second one: "EGR (exhaust gas recirculation) bypass a part of exhaust gases to the intake to reduce the maximum temperature in the cylinder and reduce the nitrogen oxides emissions." I can't reduce the size of the text, it just pated out bigger.
So the question is, if you get all this carbon buildup in the engine, does that increase heat and lead to head gasket failure?. Or if I remove the EGR will that lead to higher engine operating temperatures and lead to head gasket failure as well?.
I'm not trying to contradict you here because I don't know much about cars, and I prefer knowing from people that know more than I do. So if the EGR has nothing to do with keeping the engine temperatures lower, I'll take it out tomorrow and get the best of both worlds.
Sorr about that moderators, I can't edit that post to fix it.
@MountainManJoe thanks for your reply, that really clarifies it.