Diagnose my ailing Sidekick...

I'll try to be brief. It's a '97 Sidekick Sport with a fuel injected 4 cyl and an automatic transmission.

Had an episode a few weeks back where the temp gauge spiked up to (but not INTO) the red for about five minutes then returned to normal when I got onto the interstate. Took it to the shop and was told it was half a gallon low on coolant. It was running like CRAP at the time. No guts at all. Topped it off and it ran low again a couple of weeks later, but the sound was diminished and it performed better after it was topped off. The second time the shop did a pressure test to locate the coolant leak and found the water pump bad. Replaced it. Things improved but it's still not "fixed". The persistent symptom is that there's a noise under acceleration that's extremely hard to describe. It's sort of like the sound of crumpling aluminum cooking foil really fast. When the car was low on coolant this sound was louder. When it was full of coolant it noise is present but not as bad. The sound reminds me of knocking but the sound isn't "slow" enough for knocking. It happens every time the accelerator is depressed (not when coasting) when the car is up to temperature. It's not as bad when the engine is cold. At highway speeds it accelerates better than it did (since the water pump change) but it's still not what I think it should be. So basically the car is making a sound it used not to, but it seems tied to:

A. poor power at highway speed

B. whether the car is full of coolant

C. whether it's up to operating temperature

D. was created at roughly the same time as the water pump failing

I'm wondering if maybe the head gasket is leaking causing low compression, but how would the engine temperature affect that? I'd think cold metal would have looser gaps than a hot engine, not the other way around....?

Block and head same material? I'm not they expand at different rates. That would make it seem possible to leak more when warm.

Does it burn coolant? I'm wondering if you have a coolant leak into the combustion chamber.

Common problem on these...though I don't remember specifically if it's the head and/or gasket. I had an 88 Sidekick that exhibited very similar symptoms, and after trying a thermostat, compression check, etc. I kicked it to the curb. Only afterward did I stumble upon the solution online & that it was a fairly common issue on the 1.6L engines.

Compression test and leak down tests will answer your question.

Also knock can sound exactly like you describe. Try listening to it through a knock sensor.

I finally got fed up and took it to the shop. They tested it and determined the head gasket is NOT leaking but verified that I wasn't hallucinating. They think the lifters are bad and are giving me an off-the-cuff estimate of $2K to do the head/replace. I'm wondering if I might be better off with a remanufactured engine. Any thoughts?

In reply to stroker:

That's insane. I can't imagine a new head being more than $500-$750(if they're available) or less to refurb a used one. You can swap it out yourself in an afternoon, these are about as complicated as a WWII-era Jeep.

Just because my FI Samurai made a sound that I could consider similar to your aluminum foil, does it get better if you run premium fuel?

BTW sidekick sport isnt a 1.6 g16b it should be a 1.8 j18 and for that $2k number just buy a j20 and swap it in as it will work with the factory ecu and is bolt in.

I'm going with BHG or damaged head. Could be warping when hot and sealing when it's cold. Is it still losing coolant?

Are there hydraulic lifters or followers on these motors? I am not familiar with that lump.

Google says hydraulic lifters on the 1.8, try putting a quart of ATF in the crankcase and driving it around.

Or add a quart of Rislone.

Bump.

This is driving me insane. When the engine is cold, there's no knocking. When the engine fully up to temperature, it will cruise with no noise. Under load or mild acceleration it knocks like crazy. If you floor it, no knocking. To me that says the fuel mixture is not correct, but now I'm thinking the ignition may be the problem. Does it have an ignition adjustment keyed to the engine temperature/fuel mixture?

In reply to stroker:

Coolant temp would definitely affect fuel mixture. I suppose it's possible the temp reading is being bypassed under full-throttle. Although usually low-temp would cause it to run rich, so if it's knocking after warmed up that seems odd.

Ignition would be set by cam/crank position & RPM, although engine temp might factor into it too.

Sounds alot like spark knock. Try running 93 and see if anything changes?

Do you have a scan tool that will do live data? Kinda sounds like a problem that only occurs in closed loop, which points to a sensor problem. Maybe a bad knock sensor or wiring issue? I'd think it should be pulling timing if it's knocking under those conditions.

When's the last time the injectors were cleaned?

Took the car for a 60 mile drive today. It's ticking all the time like there's a stuck lifter now. I've tried Marvel oil but it didn't help the presumed stuck lifter. I've tried higher octane straight gas with no ethanol to no effect. BY, the shop claims it's not throwing any codes at all. WTS, I don't know if/whether the injectors have been cleaned/replaced. I'm going to check that and the last time I had the plugs replaced when I drop it off at the shop tomorrow.

In reply to stroker:

Just to be clear, it's not consuming or loosing coolant at this time?

Have you had the valve cover off to inspect things?

This Suzuki is obd2 equipped, so if you have a smartphone you should get a Bluetooth obd2 dongle and get the free torque app. You'll be able to see whats going on with the sensors in closed to real time.

Things that could be causing a lean condition are a faulty engine coolant temp sensor, an air leak in the intake manifold or inlet tube if it has a mass air sensor.

Does this have a distributor with mechanical advance, or vacuum retard? It could be stuck in an advanced position or failing to retard under engine load. Are the cam chain or chain guides badly worn causing a timing problem? You said it has a mechanical sounding noise, so that should be checked ASAP.

O2 sensors can fail without causing an engine light. They usually cause a rich condition when that happens, but it's not impossible to go the other way. How is the catalytic convertor? I would hope that an obd2 engine would give a fault on a plugged convertor, but again, its not impossible that it would miss it, especially if the downstream O2 sensor were flaky.

The shop just emailed and says the timing was off by 30 degrees. Haven't been able to quiz them on the cause or prevention of it happening again. My question is, shouldn't the onboard diagnostic throw a CODE when that happens....?

Wow 30 degrees! I'm surprised it ran and didn't suffer a catastrophic failure. I melted a piston at a track day with 3~6deg too much advance at high revs.

That doesn't sound right to me, if it's the 1.8 it has coil on plug, not a distributor setup where you need to set base timing*. I don't see how ignition could go out of time unless the timing chain jumped a tooth and then it'd throw a P0016 cam-crank correlation code.

*And in that case they tend to have the hold down bolt in a slot that won't let you adjust it that far off.

... unless they forgot to set a jumper or something to put it into diagnostic mode before checking it? Is that still a thing?

Valve timing couldn't be that far off and still run. Timing should be controlled by the ECU for COP ignition. If they're reading running ignition advance and expecting 10 degree BTDC, then you need a new shop.

Needs a compression and leakdown test.

If the valve timing IS in fact off, then how? Chain or belt skip? That's a symptom, not a cause and you still need to baseline the engine health.

The repair sheet sez: "Timing off, too advanced. Tried to set timing, one of the bolts holding cam sensor stripped out. Extracted bolt and replaced. Set timing to spec. Engine has considerable valve train noise, needs valve clearance adjustment. Suspect timing chain may have jumped a tooth."

Seems to run MUCH better now (I only went around the block) but the valve train is ticking something fierce...

Yeah, you should probably park that one for now. Noise could be the chain flapping around. Pop the valve cover off and check the cam timing and chain tension before something that could be failing does and it bends the valves.