what do you think cools the exhaust gases, coolant from the head ( thus the term "cooler") I've replace dozens of these because of coolant leaks. it is a heat exchanger type system, the gases flow thru the back of the head which is surrounded by coolant to cool the gases b4 entering the intake to cut down on nitrous emisions. Its the big plug under the cover and the coolant nipple on top that leak. Once the plug starts leaking, it gets bad real quick. take one off the back of the head and you'll see how it works. most ppl never change this gasket or reseal the plug when doing a HG job, only to have it leak at a later time causing more problems. I've even seen the plug leak and coolant get into the intake causing major problems, one time it actually hydro locked the motor the leak was so bad. Thats from 15 years of actual toyota dealership experience.

i seem to recall having to remove that egr cooler plate in order to surface the head , i agree with the guru , i think coolant was in there.. but its been a few years..and im not 100% positive..

Originally Posted by ddmcse
coolant doesn't flow through the EGR cooler
exhaust gases flow through the EGR cooler " Exhaust Gas Recirculation"


btw ........this is reason number 2 why i do not take my car to a toyota dealership

reason #1 for not going to the toyota dealership is :

i don't like to pay top dollar for # 2 work

did some research, disregurd my above statement, it was all carbony inside the cooler cover from exhaust gasses, I will admit I was wrong.. forgive me all lol...