Hi all, my rocking engine seems to come and go. Disappeared for months and came back. It seems the cold environment makes it knock at startup. I have no white exhaust, and no decrease in coolant levels. I will look underneath the radiator plug tomorrow. But the last 2 days when it’s really cold in Washington where I drove to the last 2 weeks, it’s started up knocking and I can hear the fluid from inside the cabin. It settles down and I don’t hear it again after startup. I am guessing it’s a head gasket issue but I am not 100% sure until I can do the bubble test or take the header apart. A failed header seems to show these symptoms: 1. white residue on radiator cap. 2. bubbling from the radiator 3. White smoke from exhaust pipe 4. Coolant loss seen from overflow. My option was to throw in some quick header fix. But I don’t want to plug up my pistons either. Not sure how I can tell if my oil is leaking and mixing with my coolant. It will get me home until I can replace the header if it is the header at least. Located a harbor freight that has the exhaust gas tester and will buy it to see. I don’t have 3 or 4. Haven’t had any check engine lights on to throw off codes either. Hoping it’s not the head gasket but dirty EGR so I can at least drive it home to fix. Any thoughts?
Personally I don't like mechanics in a bottle but in your situation being a long way from home I would be tempted to just try it. It is however a nightmare to clean that stuff out of the cooling system afterwards.
yes, if it’s cleanable. Going to have to make sure there’s no engine oil mixing in with my coolant. Most YouTube videos conveniently leave that out before pouring this stuff into the radiator. A seized engine would be even worse.
I experienced the same thing, had help from others from one of the Prius meet ups, cleaned the egr circuit and manifold plus added oil catch can, no more knocks. Seriously thought head gasket was bad myself, now almost at 200,000 mi
It's high. 80% highway miles at 170k. It's time for preventative maintenance. I've done the bulb compression test with the radiator. No exhaust gases were detected with the block tester kit. No coolant loss, no oil loss. No smoke from the exhaust. The only thing is the occasional knocking at cold startup once in a few months it seems. My next step is to clean the EGR, valve and intake outlets a bit tonight. Hopefully that will be the issue with the EGR and I can drive home.
I am hoping. So far the other signs are not present. Not sure how accurate the block leak test is but it made me feel a little better. Will clean the EGR and later install the catch can. Where did you get it and where did you install yours?
Oh boy, I don't envy you with this post. Far away from home and (perhaps major) repairs. If no white residue on the oil cap and the radiator exhaust sniff test passes, that is a good sign for no head gasket leak. To go further, Harbor Freight Tools sells inexpensive video cameras where you could inspect the inner cylinders; water leak would have that cylinder extremely clean of carbon. Yet you write "header" so maybe my comments are of no help. I can also say I have no experience with zero degree weather effects on a car. Also no experience with EGR and 170K mileage Prius'. The hear fluid (bubbling) is a clue. Just maybe the anti-freeze-to-water ratio is off for the temperature conditions and the bubbling is air bubbles? So maybe a drain and refill? $100 dollar cost if DIY? Don't forget the invertor has coolant, which I believe is a separate system from the engine system. All I can say for knocking is that is typically detonation, unless the damage is done and you have a connecting rod issue or, but I doubt, a valve is hitting the piston top, but you could have a failed valve spring or like. If a head gasket and you need to travel 1000 miles, perhaps the worst case could be you warp the cylinder head. I would not expect a hydro lock issue. All FWIW, maybe of no help, but good luck.
Thanks! I appreciate the response either way. Took it to a home mechanic. Not sure how helpful he was as he didnt have the tools do do a leak down test or compression test. All I have is Autozone readout telling me I may have an ignition coil issue or bad spark plug in cylinder 1. I paid for another oil change. Cleaned the EGR valve since I dont have the tools or time to fuss with the screw from hell to take out the EGR or the intake to clean. The dang car didnt make any noises this morning at the guys shop/house so he couldnt diagnose anything. He just told me its unlikely a head gasket issue even though it has high mileage. He said there should be rattling and knocking on every startup not just a couple times off and on in cold weather. I did all the easy tests I can do and looked for easy signs. Will stick in half a can of Sea Foam into the oil and see if that helps burn off some carbon.
Unless you have money to burn, I would find out what specific problems the additives are addressing (and whether you actually have any of those problems) before spending any money on them. Many reviews for these products are along the lines of "I've been using this for X years and have never had issues". Yes, it will likely not do any harm, but did it actually do any good?
It sounds more like an ignition coil or spark plug if you're not ever getting any white smoke or losing coolant. Someone mentioned looking inside the cylinders with a bore scope and I didn't see any mention of it again. That's actually a very good idea since other tests seem inconclusive. If the HG is leaking into the combustion chamber, that piston will be steam cleaned. BTW, there is no header in a Prius or in any non-racing car. I assume you meant head gasket? As for the stop leak stuff, I don't think I'd want my engine looking like this.
I’m thinking sticky pistons. I have the same issues. I’m going to try bg hybrid repair kit. After I figure what I plan to do first. Were you able to fix ur issue?
liquimoly engine flush dissolves sticky gunks and will smooth out your pistons. Then add liquimoly ceratec. Liquimoly is a german brand mainly used by luxury (problematic) vehicles like Audi or BMW.
