Extreme vacuum in coolant system

When you replace the spark plugs the quickest test you can do is touch your tongue to the tip of each spark plug you'll taste coolant on a couple . No you won't die I do this all the time maybe it'll make you as crazy as I am possibly I don't know but vacuum doesn't have much to do with the funny business at all hoses generally aren't going to collapse in the Prius the cooling system is quite a bit different than a regular car although it is still a cooling system but yeah you'll definitely find some coolant taste on a couple of the plugs and then when you pull the head if you bother with that you'll see the damage If you want to get a boriscope that's got good resolution you may have a crack at it with that usually I just blast the head off see the damage and get ready to pull the motor That's a fairly quick thing to be doing.

 

On a side note, whenever you get the head gasket sorted and working, you next failure will be the hybrid battery from sitting too long

 

What’s the miles?

 

Generally in these modern engines a lot of times you can have head gasket seepage enough to quench the fire in the cylinder but yet not turn the oil to look like coffee with creamer in it matter of fact the last time I've seen that has been a long time ago in an old hemi head 2TC 1.6 Corolla motor circa 1975 so it's not real common since the invent of modern engines that you see this extreme mixing of oil and water unless there is a huge crack a large void where water can literally vanish from the The reservoir and into the engine usually on the Toyota's like this you don't lose very much coolant and it's over quite a bit of time so it's a little seepage enough to cause the death rattle make the car run poorly but not flooded kill it and make the oil look like coffee was cream.

 

Pulling the orange plug (a fuse) doesn't do much....

 

A blown head gasket won't always show coolant in the oil. Does it rattle/shake when you start it? Are you losing coolant?

 

Pressure test the cooling system.

 

The suction from the coolant reservoir is because it's losing coolant... This is normal because Toyota failed horribly at "improving" the Gen3 engine. The EGR system gets clogged, the piston rings burn oil before 200K and there's no such thing as a 300K mile club for Gen3 Prius.

The good news is its just the gasket that's usually failed between cylinder #1 & #2 and some people can go years with this problem without much issue if you avoid hot weather and long drives. Once the engine starts running really rough consistently that's when you can destroy the dampener in the transmission if you keep driving it.

Best long term solution is buying a low mileage Gen4 engine from a wrecker and there's a mobile mechanic on here who's based out of Oklahoma who will swap the engine in your driveway in one day for $1500.

 

Head gasket fails are more common than a bad plug after 200k mile use on either. Sealers are sometimes used to flip gen3s with additional problems resulting. Oil burning from flawed rings, brake booster and inverter fails were all acknowledged and fixed free by Toyota in the early years.

 

When you replace the spark plugs the quickest test you can do is touch your tongue to the tip of each spark plug you'll taste coolant on a couple . No you won't die I do this all the time

Dang, learn something new every day!! I'll be changing plugs, icwp and coolant control valve in a Gen 2 tomorrow (just did the brake actuator). Maybe I'll give 'em a taste test just for the fun of it.

 

Don’t do the taste test. I haven’t seen a coolant lately without a bitterant added. Gonna be nasty!

 

Won't taste the bitterant if there's no leaking coolant....