Unplug EGR Valve

If you are losing coolant it is at an advanced stage. Sealant might work for three months if you are very lucky.

The insidious thing about sealant is it seems like a miracle at first and people get false confidence. A couple of months later they repeat because the rattle returns. Pretty soon it's junk the engine or car. The car because the radiator and heater core are messed up.

Bottom line, really save for another car in three months regardless of how great the sealer seems.

 

but this was a trail of fluid for a long stretch of gravel road. it was dark enough and wide enough that I thought my coolant was empty but when I looked it was fine. even checked the oil and its fine.

 

What color is it? If it's dark, dark what? Brown? like engine oil? Red, like from the transmission?
The coolants don't get a dark color.

 

Coolant leakage can occur due to damaged hoses or too high engine temperature, when it will be released through the relief valve on the radiator. What was the engine temperature at the time?
Do you use any diagnostic tools?

 

EGR 的主要目的是降低燃烧温度，搜索它你就会知道。不值得拔下电源插座。

 

Translated into English:

EGR The main purpose of is to reduce the combustion temperature, search it and you will know. Not worth unplugging the power socket.

 

I might say it almost the same, to slow down the combustion. Ideally all the fuel molecules and all the air molecules are still going to find each other and react, but because of the exhaust gases with their own noncontributing molecules in the way, it takes longer. So there's a slower steadier burn pushing the piston down instead of a big flash near the top. The total energy gets released either way, but the fleeting temperature reached during the hottest milliseconds of burn is lower.

The temperature reached by the engine materials (block and head and valves and coolant, etc.) depends more on the total energy released in the burn than on its millisecond-to-millisecond fluctuations.

 

Amazing discussion in this thread.
My Prius used to have cold start rattle (hg), paid gasket Master fixed that. After 3 years, now it cold start fine still and coolant level stable so far, but during driving when starts from stop at times will have a small rattle (jerking/jolting), I also noticed slightly lougher idle some times. I think it is very similar to some comments here.
I want to try to do the metal spatula block test, but I am scared about the spatula cause problems. I will try unplugging the electric EGR connector to begin and run a tank of gas and report back.



I am also not sure if all the exhaust from all 4 cylinders got through this EGR thing or only of part of the exhaust goes into EGR and part of it goes through cat and outside, or is it all exhaust goes through cat first, then EGR?
If the EGR is always closed (either mechanical or electrical methods), then will the exhaust get blocked and overheating the EGR cooler? Maybe the exhaust gas will be blocked by the valve and never entered the cooler?

 

How many miles has it been since you cleaned the EGR system?
Depending on how much oil the engine is burning it should be cleaned at
about 50,000 miles.

What about the spark plugs? How many miles on them? Are you certain they are not
the cheap chinese copies?

Spatula block test? Never heard that.

 

All of the exhaust from all four cylinders enters the exhaust system and mixes. The EGR is taken from a small port on the side after it has mixed. The rest goes through the catalytic converters, EHRS exchanger, resonator, muffler, and out. When no EGR is being taken, 'the rest' is all of it.

In gen 3, the small EGR port comes before both catalytic converters. Gen 4 moved the port to between them.

 

The link below shows a quick block the egr test with a blade. It is intended to eliminate a stuck open egr valve as a cause of low rpm stumbles or start problems.

This link was modified to start at the block egr quick test

The entire video is a good description of a Toyota Master Mechanic's view on gen3 egrs which is shared by many of us and many pro shops.

There is little doubt that gen3 oil consumption problems can lead to total clogs of gen3 egrs. It is also common knowledge that the gen4 egr redesign combined with better pistons and rings eliminated the need to clean egrs as a preventive measure.