Head Gasket

I’m having trouble diagnosing my misfire. I have already changed the spark plugs, the plug wires, and injectors. The only thing I haven’t touched is the coil packs because they’re pretty new. Less than 10k miles. I have the feeling it might be a head gasket, even though I don’t have any signs of it. My coolant was a little low but there’s never any smoke coming out of the exhaust. Any help is greatly appreciated!

Also, i hear a slight hissing noise above 3k rpms from inside the cab. Sounds to be coming from the driver side. The misfire is usually really bad at cold start and smooths out. Still sluggish and slow above 3k. Seems normal below 3k rpms.

 

get a cooling system pressure tester from Amazon or borrow one from a part store...
Get a boroscope from amazon, etc...
They make them to work off your phone.
Get vehicle to operating temp & shut her down.
Pressure test cooling system to about 20psi & let it sit overnight under pressure.
If it bleeds down, pump it back up....
After the truck cools remove spark plugs & start looking for coolant intrusion through the sparkplug holes using the boroscope.

Theres another test called chemical test / block check...
Lower your coolant level so about 4 inches down so you dont suck coolant into the test tube...
You fill the tube with blue "block check fluid" & you place it over the radiator fill & make a good seal...
Pump the bulb, over, & over, & over, & over....
Sucks the gasses "hydro carbons" into the test tube & if it detects HC from a bad head gasket the blue fluid will change colors & turn to piss yellow.

Theres a slight learning curve to do the block test well but not hard...
Sometimes you could have a bad gasket & it wont turn, I have zero experience on doing the test on any toyota but have done the test probably 5K times....

I get the vehicle hot buy going on a long readiest, without ending up in the emergency room with third degree burns from the hot coolant.....
Right after the roadtest you remove the rad cap & immediately put the filled tester on the radiator & try to get the accumulated initial gasses & try to turn the chemical.

If youre scared to do it that way, dont drive it, get to operating temp & try....
Test result will not be as accurate...



The boroscope looking down the cylinder is much easier if you have a check engine light on & know what cylinder to look at versus looking at all....

Also if you truly have a misfire, your CEL should be on...

 

That post wore me out...

 

But it was good info.
Well worth the finger workout....

 

Thanks for the quick replies! I was going to borrow my friends boroscope tomorrow to see if I can see any coolant in the cylinders. I’m also going to try moving around the coil packs. It wasn’t getting a cel before but now it gets it pretty consistent after i clear the code.

 

I also tried used the Hydro carbon tester but I rented it from autozone. It was leaking and I think there was a crack in it so I’ll probably get another one and try it again.

 

So you know what cylinder hole had the misfire so youre not shooting in the dark?
Boroscope without a pressure tester will be a waste of time...

& dont put your buddies boroscope down the cylinder of a hot engine....
just saying..
seen it done..

I live the simple ones, like this....
Some of the hocus pocus ones ones have multiple chambers, drama....

$38 Block Tester BT-500 Head Gasket Combustion Leak Test Kit - Made in USA

https://www.amazon.com/Block-Tester...&hvlocphy=43832&hvtargid=pla-4583932709121118

 

Yeah i get a different code sometimes but it’s either po302, po304, and po306. I also got a po300 once. I’ll look for a pressure tester that i can order. I was going to see if I could see any coolant in any of cylinders but seeing how there’s never any smoke out the exhaust, it’s not worth looking.

I’ll also get another combustion gas tested to check that again. When i’m warming up the engine, do i keep the tester on where the cap on the radiator goes?

 

Yes, just locks onto the radiator fill.
I think some auto part stores loan them out....
Pay no attention to the bleed-off on the gauge, sometimes they dont seal well & theyre going to bleed down regardless if you have a leak or not.
Some people are just fixated on #'s...
Means nothing if youre not certain / familar with the tester & you know it doesnt bleed down over time.

Basically youre just using it to squeeze the coolant out of the damaged head gasket area, if there is one.
Sometimes its nothing more than a slight mist, over time.
So if you dont have access to way up high where the head gasket is, will take some time to see it collect on the top of the piston...

 

You could also borescope cylinders 2,4,6 looking for steam cleaned pistons. That will be a dead giveaway that your head gasket is cooked.

The way you describe the issue it might be too soon for the steam cleaning to have happened, but if you already have the borescope, may as well take a look

 

Ok I will check that and try the tester again. If the head gasket is the issue, should I take it to a shop? Or should I try to do it at home? I haven’t done too much engine work but I know the basics of an engine.

 

Nobody can answer that for you....
We all have different skill sets...
Im sure plenty here have done them successfully & correctly, while others attempted & have made matters worse...

I was a ford engine guy my entire career...
Ive done multi thousands of head jobs on fords, im very capable to do a toyota head / heads....
Would I want to, absolutely not....
If it were mine, ide start digging for someone who knows these engines like the back of their hand...
Ide pay & hav them do it, but thats me....

I dont have the mindset that I can do it better than them, & im not paying someone to do it...
my 2 pennies...

 

I don’t really want to do the job but the shop quoted me 1700 for just the labor. Also said if the heads are cracked it could be a lot more. I’m only 16 and this is my first truck. I already have a lot of great memories in it and want to keep it as long as possible. Hopefully the issue is something a little bit cheaper or easier but i’m worried it’s going to be the head gasket.

 

$1700 isnt bad,
Also get a few more quotes...
In some areas some people dont realize engine rebuilder / machine shops also do engine work in the car...
Thats another option...

 

Welcome to TW…

 

I’ll look at other shops but I live in a kind of small town and there’s not a lot of shops out here. The shop i called recommended just selling the truck but i want to keep it. I’ll see how things go.

 

Did they offer to buy it?