Driving to work this morning when suddenly and warning light goes on and "low coolant" appears on the dash, and the temp gauge spikes suddenly. I pull over as quickly and as safely as I can. I manage to get a coworker to bring me some coolant, refill it but when I start it back up its just puking it out, and now the engine is misfiring as it idles.
I call AAA and use the last of the four tows I get for the year to tow it home and call off work for the day. I have to drive it for a min just to back it into the garage, and now its knocking as well as missing.
I'm starting to pull things apart right now, coolant leak seems to be coming from under the throttle body on the passenger side, there is a line coming out the firewall that I think is the culprit. But as I pull off the intake to get in there to examine closer there is a lot of blow by coming in through the head breather. Not enough that the intake track is coated with oil, but a significant enough amount to worry me, especially giving the knock.
Code reader produced the following codes p0300 multiple random misfires, and p0301 through p0304 misfires on cylinder 1, 2, 3, 4, as well as p0705 trans range sensor, but i think that last one is unrelated. I've also got pending codes for p0305, p0306 & p0308, misfires on cylinders 5, 6, & 8 and p1316 and p1111
I'm going to see how thing are once I fix this leak, but I'm not hopeful. I think the motor is done.

 

Ok so I've got the throttle body off and I can see in there a bit better, looks like the line I suspect, is a hard line that connects to a hose that runs under the super charger. If I have to remove the super charger to get to it I want to confirm first that that is where the leak is, but with the intake and throttle body off I'm not sure how I do that.
If I plug up the coolant lines I've removed from the throttle body I wonder if I can crank it enough to start moving water through the system and try and spot the actual leak. Thoughts? Any other suggestions?

 

hey to replace those hoses i just did that about 4 months ago and i had a how to thread i posted with majority of the information...it took me a while im not going to lie...did it myself changed a lot of stuff during, vac lines, coolant lines, water pump, thermostat, SC oil, coolant, spark plugs, air filter, cam cover gaskets, coolant cap....it was a tune up took about a month and half... tear down was about a week or so and waiting for parts to arrive and all...try to find it if you can...if not ill post it and if you have any questions ill be happy to help! good luck...i just had the coolant leak no misfires or anything and my leak was indeed under the sc the two hoses that run through the valley.

also perhaps the coolant got to your knock sensors throwing them off?? thats why its misfiring in both banks??? just a guess...first thing i would do is remove the spark plugs and look inside the cylinders if there is any evidence of coolant...because that could mean a head gasket. and do you have an idea of how hot it got? when i lost all coolant mine reached 232F ...at 245F is when the gasket starts to fail and warp. its basically luck from that point on. but i was able to recover from 232F.

 

why not pressurise with a garden hose and dispense with
the risks of starting the motor?

 

I have no idea how hot it got, but the temp spiked really quickly, I saw the temp needle rise from normal right up to red in a mater of seconds. I pulled over as quickly as I could and shut it down, but I was in the middle lanes of the freeway and had to navigate through some traffic in the right lanes before I could get it off to the shoulder.
I'm going to pull out the spark plugs and check for coolant. Also drain the oil and see if there is any coolant in there. If the head gasket is blown, no point in going through all the work pulling the SC. And if that is the case I'm not sure it's worth my time and money fixing a head gasket, I may just be done with the car at that point, and get rid of the thing.

 

that is understandable....the condition of the car...your love for the car...if you can put the time in ...etc....but good start check for coolant first and get back to us....all in all i only put about 350 dollars during that tune up...hoses itself are about 50-60 dollars for both. its the labor that kills and if your willing to put in the time and effort and the car is in good/great condition where it should be saved then for sure. but i agree head gasket ...will not be worth the repair. do a compression test in each cylinder..once you can confirm about the coolant...*fingers crossed*

 

Things still don't look good. I pulled all the pass side spark plugs, no signs of coolant, but every spark plug had fresh motor oil on it, with the 2nd one back (sorry I don't know the cylinder numbering) being absolute coated in oil and coming out dripping. Perhaps a ringland cracked, or it spun a rod. I'm not sure really where to go from here, its looking more and more likely that it is going to need a rebuild, I don't know how much further its worth going trying to fix this thing.

 

BobRoy, another member here PMed me and told me to give him a call, after talking through a few things with him he made me realize that the engine might not be so bad.
When I removed the oil covered spark plug, there was oil on my spark plug socket, so the oil must be coming from a leaking valve cover, and not from the cylinder, the heat must have finally done in an already aging valve cover. And with the spark plug tip saturated in oil, it was not able to produce a spark, hence the misfires.
I'm going to pull the valve covers and replace the gaskets and o-rings around the spark plugs, and keep going with removing the super charger and finding and repairing that leak.
Going to be a lot of work, but I'm much more confident now that I can get her back on the road.

 

Well did a compression test before doing anything else. Started with the pass side cylinders, from front to rear it was 120psi, 115psi, 120psi, 0psi. No compression on the rear most pass side cylinder. I didn't bother testing the driver's side after that, motor is done.

 

Humm. Two possibilities there. Hole in the piston....not too likely. Valve sticking open, much more likely with an overheated engine. Also not all that big a deal although I have no idea what the cost is.

 

You may have dropped a valve seat, and the head gasket is a common failure when overheating. It's worth pulling the heads to inspect. I would check compression on the other side first.

 

You might find something like this would make a good diagnostic tool
https://www.amazon.com/BlueFire-Andr.../dp/B013HZCYXK

It's available for either android or IOS. take a peek w/o removing heads.

 

I not really sure it's even worth diagnosing further. If its a head gasket or a rod bearing it's not worth the money to fix it. The car is only worth a few thousand. Best option would be to maybe take a gamble on a used motor. I'd sell it as a parts car but I have no idea what it would be worth, and it will probably take awhile to sell. I may just donate the thing. I won't get much for it but it would be the easiest way to get rid of it.
It's been a fun if not brief adventure with this jag, but I think this cat will leap no more.

 

Well, not knowing what else to do, I continued with the compression test this afternoon on the drivers side. From front to back I got 115psi, 118psi, 115psi, 100psi. Slightly low compression on the last cylinder and again the 2nd cylinder back the spark plug was covered in oil, came out dripping.
I drained the oil and there was no coolant in it, and also no metal filings, so at least there is some good news. I'm going to pull the valve covers and see if the spark plug o rings failed and if that is the reason for the oil on the plugs, then possible pull the heads.
If the bottom end is ok, and the heads didn't warp and I can just replace the head gaskets and rebuild the heads, then it might be worth saving this motor. But if the bottom end needs rebuilding or I have to redeck the heads or do any other machine that requires tearing down the rebuilding the motor, then its just not worth it in my opinion.

 

Happy to see emotions cooled down, and you give it an other try saving the old girl. Good luck in the process.

 

So I've got the super charger off and the two hoses running under it don't show any sign of cracks or tears, so now I'm completely confused as to where the leak is. It would be a shame to get it all back together only to have that still leaking.
Still haven't got the cam covers off, they seem pretty stuck on there. I've removed 12 bolts along the outer edge of the cover, plus two in the middle around the spark plug, still can't pry the thing off. I think it is "glued on" with RTV gasket maker.

 

One other thing to mention, the temp sensor on the water outlet hose broke off while I was trying to unplug, it just snapped in half. I don't know if that is the sensor for the temp gauge, but I wonder if this sensor was going bad and that's why I saw the needle just shoot up from normal to red in a second instead of climb slower. Perhaps it wasn't able to read anything below a certain temperature, if that's the case, who knows how long and hot hot it was running overheating for.

 

I just went through an overheating case myself, and can confirm that the interior temp. gauge is all-or-nothing.
I observed some strange behavior of the fan the days before, so I ran my Torque Pro monitoring the temp. constantly.
I saw the temp rising, while the interior gauge remained steady, only to shot up all of a sudden.

I just read your post again, and it sounds a lot like mine, something I did not catch before.
In hindsight, my thermostat failed to open (confirmed by a boiling test in a pan of hot water), which let the coolant get hot in the short circuit (without the radiator system).

When I turned off the engine, the temp. and pressure got so high, that the coolant was pressed out to the external overflow tank so severely that a huge fountain of coolant sprayed back in the engine bay.
That also set off the low-coolant warning as the main expansion tank was simply empty after that .

I also suspected a leak, as the coolant remains were everywhere, but after a clean-up and check after check, non of the hoses was actually leaking.

From what I read, you got it in time, I should not worry too much about it right now, and concentrate on what you are doing checking the valves.
Check ur thermostat though!

EDIT: Maybe you can break the seal of the valve covers by running kite-wire through it, to 'saw' it open.
Just be very careful to clean out everything, it will be a mess.

 

So I've removed the cam covers. I don't see anything glaringly out of place, but to be honest I'm not sure I'd know what I'd be looking for.
More worrying was the fact that the spark plug oring seemed to be fine on the cylinder where the spark plug was covered in oil, so a bad gasket doesn't explain away that. Same case on the oil soaked oring on the drivers side. Looked fine so why the oil?
Not really sure where to go from here, pull the head I guess? Anything I should look for before that to diagnose this now before I go any further?
Pic of the cam cover removed and the valves on the zero compression cylinder, although I don't know if anyone can see anything from a picture.

 

Yes, pull that head is the next step