2010 possible head gasket

Hey y'all,

I am a new gen 3 owner, long time gen 2. Learned a lot by reading stuff here but wanted to see what you thought about my new purchase.

2010 ii, 210k, $2500, decent shape, runs and drives.

Story:
guy lives in mts, at some point it overheats and losing coolant. He takes it to mechanic, they give him run around and offer to buy it for 2800. I figured I can get a motor cheap enough to make this thing sound, but now I think it might not even be bad head gasket. I didn't drive it because the knocking scared me, but now I know it's"normal".

I know the guy said it lost coolant but I'm not sure if it's consuming coolant, def a head gasket, or it overheating and overflowed resulting in lost coolant

Diagnostics:
When it first started up I heard a horrible knocking that made me decide to have it towed. But I did notice that once running it appeared fine. I took it apart, checked plugs, look fine. Compression is consistent, low, averaging 95, but that's probably due to cold engine and cheap tester.

I didn't notice any water on oil cap, or sludge in dipstick so that's good news. But the pcv valve looked rusty and there was oil/water in the hose and where it attaches to intake. I'm trying to be optimistic but this doesn't look good.

Future:
I plan on removing egr, and intake for cleaning. Followed by testing water pump, and replacing thermostat. I could use a block tester to see if exhaust fumes are leaking into overflow tank, and confirm head gasket. What do you guys think?

 

Trouble codes:
P0300, misfire
P0303, p0304, cyl 3 and 4 misfire, even compression and plugs looked good, not sure what to make of it.
P0351, p0352, p0353, p0354, ignition coil primary/secondary circuit. For this one I'm thinking it might be due to battery, it seems like the auxiliary battery is on its last legs. I doubt all coils are bad

 

I thought knocking might be due to egr circuit. But I might service the injectors just in case, is that a diy with carb cleaner or take the shop?

As for ignition coils I'll check to see if they are in spec and replace as necessary, they are kinda pricey. Plugs look okay too, but rockauto has em for cheap I'll likely replace.

Can't say anything about the white smoke because I was afraid to drive it at first due to the knock and possible head gasket. But It does seem like a good diagnostic now, considering knocks are normalish. I might let to let it run to operating temp, check the fans, block test, check exhaust gases. I can always let it warm up in my driveway wth cowl removed so i don't have to work twice.

Thanks a lot for your input

 

Almost forgot I didn't get hv, but no trouble codes for it yet. I'm hoping it's fine, if not my gen 2 battery is in impeccable shape, it's actually a low mile gen 3

 

Water pump inspection:
Simply use techstream to test that it spins. Considering it costs 200 dollars I don't want to replace it unless it's leaking or not working. Thermostat is cheap and a good to replace. This thing overheated for some reason.

Coolant consumption:
I don't know, but I can use diagnostics to try, since I'd rather not drive it with bad head gasket. So far good even compression is a good news. Once it's cleaned and running I will run a block test on radiatior fluid to test for exhaust gases. If you can think of a better way I'm all ears, that's why I posted .

Battery:
The gen 3 modules are in my gen 2 prius, I recently viewed live data. The difference between highest and lowest voltage module was .15 v, I would say that's darn good. I think they are from a 2013 or 2012

 

Coils:
I hadn't done anything with the car, I basically got it home, read codes stored data, and erased. I know there's some things that needed to get done so I'm inspecting, replacing things as needed, then I'll run it and look for codes. I probably won't replace them unless they are out of spec due to cost. Although junk yard is a good idea.

 

Update:
Got the car running with all lights off.

Repairs:
Cleaned intake manifold, egr, egr cooler, assoc pipes, changed pcv, changed thermostat. I did not clean injectors. I wanted to see how it ran without it seeing as how removing injectors will be the same with manifold on or off.

Current state:
Appears no overheating as of now, runs well, but horrible knocking on cold start ups, despite being warmed up earlier in day. I live in California It doesn't get very cold. 60 to 70 f right now.

Plans:
Get an oil catch can. It seems people are reporting mitigation of knocking. It's bad knocking and knocks every cold start

Side note:
I had an abs light, for c1203, c1345. I went into techstream to perform solenoid valve relearn. It solved all my lights. It's done under active test under abs pcm takes 120 sec to do

 

I use carb cleaner in the small ports by the larger intake port. Specifically I sprayed using the plastic pipe and went through each port. It's easy enough to remove again to clean, but I don't have a glimmer of hope that my problem is due to that.

 

That came out harsh. Don't know how to edit lol. Thanks for the opinion, I'm just jaded that cleaning didn't appear to do much regarding the knocking

 

I did a compression test on a cold engine. Compression was low, but consistent. I'm not a trained mechanic but it would be surprising to me to see consistency in a bad head gasket. At this point I'm thinking the gasket is fine.

I like those pictures. They definitely help tell a story. I might try out your method if I remove the manifold again.

 

It's like you are a fortune teller. I just noticed coolant loss. Ive driven it 500 mi and the coolant tank was completely empty. I checked it because i heard gurgling. I am more certain of head gasket now.

It must be pretty small though. I'm wondering if it's actually a small crack or warp. Any help with this would be a big help. Is there any way to know if the connecting rods are in bad shape without popping the pistons. Also should I be concerned about bearing damage if there doesn't appear to be oil water commingled?

Head gasket shouldn't be that bad, what will suck is that it's my only car. And I need to transport the head to machine shop. I guess I'll be lugging a head with me on the city bus

 

You are correct. That's probably why when it starts after sitting it gives a horrible racket. I never ended up doing a block test, I'll be doing that soon. I'm hoping it's just a head gasket. Interesting that this thing runs well (expect when it freshly starts) and doesn't appear to be habitually vape fiend