Stuck EGR Valve

Did you replace the gaskets when you put back the egr circuit and manifold?

 

Could the sound be coming from your water pump?

What codes did you have, back when the trouble started, before you cleaned the EGR system?

The shuddering hopefully isn't due to a little head gasket leak. Has your coolant level been steady?

 

If your coolant level runs low again within days or week, get a leak down test. If the result comes back with lower than average pressure chances are you got a blown head gasket, then what ever you throw at it won't resolve the blown head gasket issue. Either save up for an engine replacement or another car.

 

I can't see it causing any problems. You're basically removing a sparkplug on a cylinder at top-dead-centre of the compression stroke, then applying air pressure, seeing if the cylinder will hold air. A special 2-gauge leak-down gauge set is used (which I'm not familiar with). The readings on the gauges give some clues, and you also just look to see where the air is leaking, if it is.

Still, considering the miles at which you cleaned everything, the dropping coolant, and the p301 code, it's pretty much a certainty you've got head gasket failure, cylinder one. The EGR passageways in the intake manifold (roughly 1/4" diameter, one per port) invariably clog up first at cylinder one first. The clogged port means no exhaust gas getting through to cylinder #1, and as a consequence it runs hotter. Cylinder #2 would not be far behind.

By 217 miles it would be near-completely clogged.

 

From reports here, not necessarily. There is a code for insufficient EGR flow, but:

1. It seems to come on too late, when partial clogging has been going on for some time.

2. That "partial clogging" is often total clogging of one or two cylinders (typically 1 and 2 first), while clogging is still only partial on 3 and 4. The head gasket failures are occurring with dismal regularity at cylinder 1 and 2.

 

There is a risk of hydrolock, how serious depends on the rate of coolant leakage into the cylinder. Basically if enough (uncompressible) coolant gets in a cylinder (I'd assume cylinder #1), the crankshaft will try to swing the piston up, unsuccessfully, and you'll bend a piston arm, maybe evem punch a hole in the block wall.

A non-driving alternative might be to get an endoscope, pull a plug and have a look see. Or someone who can come by with a portable compressor and leak-down gauge set.

OTOH you may be ok to drive still for a while, but it is a bit of a gamble.

FWIW, a lot of people with just failed head gasket do a full (used) engine swap anyway, because professional head gasket replacement alone can be pricey. If you're confident to DIY you're looking at somewhere between $100~800, depending on various factors.

With your miles I'd say get the full Toyota gasket kit (around $250, has the head gasket, plus pretty much every flexible seal/gasket in the engine. Also, for better safe-than-sorry, brand-new head bolts, a set would be around $100? Sending the head to a machine shop for complete rebuild (new seals on the valves, check all the valve seats) is maybe around $500??

I forget if you're burning a lot of oil. If you are maybe engine swap makes more sense. Or sell (with full disclosure) and move on. Lots of options.

Here's links to some Gasket Master videos. Not sure I like all their "table manners", and they gloss over some of the preperatory work, but interesing.

 

Will using top tier gas help prevent EGR clogging problems?


iPhone ? Pro

 

No. I use nothing but Chevron, which I beIieve is Top Tier. Had modest but definite clogging starting at 70K kms when I did ours. I think the only thing that might prevent it is trading to 4th gen...

What rankles me is the language of the Toyota Warranty Enhancement Program bulletin we got, specifically:

While the majority of vehicles will not experience this condition,

And that's exactly how it appears in the document, italicized and underlined...

 

I used top tier on our old 2010 and it didn't prevent the clogging.

I did egr circuit intervals at 130k and around 175k and that seemed to be about right.

Clean the circuit before you wished you cleaned it.