Toyota RAV4 Forums banner

1 - 10 of 10 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter #1
I have been dealing with a very tough-to-track-down misfire on what I believe is cylinder No. 2. I took the rav4 to the dealer and had it diagnosed, and they came back with recommending a head gasket replacement. They think it is blown. My question is WHY do they think that?

I have NO excess moisture in the form of water or steam leaving the exhaust when running.
I am not losing any coolant.
My motor oil does not look contaminated.
The vehicle has never overheated.
Compression across all 4 cylinders are within specs.

The dealer alleges that they scoped the cylinders and saw "small droplets" of coolant on the cylinder heads. Again, see arguments above.
I have replaced and/or cleaned the air filter; throttle body; spark plugs; ignition coil assemblies; fuel injectors; flushed/replaced engine coolant (per Chilton); and valve cover gasket.
I will say that I think the engine revs a little higher when the engine is cold (symptomatic of a vacuum issue??), but NEVER gives me any misfire symptoms until after reaching full operating temperature.

Might I have a vacuum leak somewhere? Perhaps a bad intake manifold-to-cylinder head seal/gasket? I'd much rather tackle an intake or vacuum issue than yanking the cylinder head to replace the head gasket. I ask for the kindness and generosity of this Forum's members to offer up any expertise or suggestions that may help me in these troubled times.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #2
I have been dealing with a very tough-to-track-down misfire on what I believe is cylinder No. 2. I took the rav4 to the dealer and had it diagnosed, and they came back with recommending a head gasket replacement. They think it is blown. My question is WHY do they think that?

I have NO excess moisture in the form of water or steam leaving the exhaust when running.
I am not losing any coolant.
My motor oil does not look contaminated.
The vehicle has never overheated.
Compression across all 4 cylinders are within specs.

The dealer alleges that they scoped the cylinders and saw "small droplets" of coolant on the cylinder heads. Again, see arguments above.
I have replaced and/or cleaned the air filter; throttle body; spark plugs; ignition coil assemblies; fuel injectors; flushed/replaced engine coolant (per Chilton); and valve cover gasket.
I will say that I think the engine revs a little higher when the engine is cold (symptomatic of a vacuum issue??), but NEVER gives me any misfire symptoms until after reaching full operating temperature.

Might I have a vacuum leak somewhere? Perhaps a bad intake manifold-to-cylinder head seal/gasket? I'd much rather tackle an intake or vacuum issue than yanking the cylinder head to replace the head gasket. I ask for the kindness and generosity of this Forum's members to offer up any expertise or suggestions that may help me in these troubled times.
Additionally, the misfire symptom occurs when trying to accelerate, or maintain speed when traveling uphill. When more power is demanded from the motor. Hope this helps a bit more. Thanks again!!!
 

·
Registered
Joined
·
8,361 Posts
Did the dealer check for thrown codes? Their diagnosis would seem to be inaccurate as you have checked for symptoms of a blown head gasket and there are none. Suspect that the dealer is attempting to make quite a lot of money from this and that it would not solve the problem. Seems that it could be a problem with the ignition system, based upon your description. Perhaps take your RAV4 to an independent garage for a second opinion.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #4
I cannot tell from the ticket whether they dealer recorded any codes, if they checked for any. I drove the vehicle to O’Reilly’s and had the codes read just to be sure/current. They are as follows:

P0302
Cylinder no.2 misfire detected

P0352
ignition coil b primary / secondary circuit malfunction.

I’m attaching an image of the dash lights resultant of the codes being thrown.
154098
.
 

·
Registered
Joined
·
3,485 Posts
I cannot tell from the ticket whether they dealer recorded any codes, if they checked for any. I drove the vehicle to O’Reilly’s and had the codes read just to be sure/current. They are as follows:

P0302
Cylinder no.2 misfire detected

P0352
ignition coil b primary / secondary circuit malfunction.
Check the ignition coil if it is bad. You can buy inexpensive tester to check the ignition coils. Ignition coil can be found on Ebay cheap. Dealers can be sneaky sometimes and try to rip you off thinking you know nothing about cars.
 

·
Registered
Joined
·
8,361 Posts
Codes read by O'Reilly's appear to confirm suspicions that the problem is with the ignition system - dealer apparently was attempting a rip-off. If the problem is a bad cyl.2 ignition coil replacing the coil obviously is loads less expensive than replacing a cylinder head gasket.Dealer's supposed finding of "small droplets of coolant on the cylinder head" after claiming to have "scoped the cylinders" makes zero sense.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #8
I replaced the coil assemblies, first with no-namers from eBay, then a second go-round with Denso OEM parts. This was all before taking to dealer to get set up for a scam, apparently. Today I’ve gone out and tested (the replaced with new anyways) the spark plugs after testing for resistance and continuity on each. I also tested the camshaft AND crankshaft position sensors for the same as the plugs. All good, per specs. Based on responses today, I have also switched coil packs between cylinder 2 and 3, and have cleared the codes. Will run it to see if I get a code that indicates a misfire on 3 in the near future. Thank you for everyone’s help and feedback! I will follow up to this post when I have more info. Please don’t hesitate to add comments as ideas pop up.
 

·
Registered
Joined
·
580 Posts
I replaced the coil assemblies, first with no-namers from eBay, then a second go-round with Denso OEM parts. This was all before taking to dealer to get set up for a scam, apparently. Today I’ve gone out and tested (the replaced with new anyways) the spark plugs after testing for resistance and continuity on each. I also tested the camshaft AND crankshaft position sensors for the same as the plugs. All good, per specs. Based on responses today, I have also switched coil packs between cylinder 2 and 3, and have cleared the codes. Will run it to see if I get a code that indicates a misfire on 3 in the near future. Thank you for everyone’s help and feedback! I will follow up to this post when I have more info. Please don’t hesitate to add comments as ideas pop up.
Jack, check your wiring to the coils too. At this point I don’t know if your RAV has been sitting like many were but reading a fault on the coil and a misfire could indicate a problem with the wiring from stowaways (the furry, hungry type). I have been seeing a lot of droppings in my engine bay lately and I have a rat that found his way in too (just found a rat poop on top of my battery today). Those bastards are nasty. OTOH, it could just be wires in contact rubbing for years wearing through the insulation.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #10
That is something I will check for. Yesterday, I checked for voltage and continuity at points 1 and 4 (see attached photo) like the on-vehicle inspection. Voltage and continuity checked out, but I don’t know how to check points 2 and 3 with a multimeter.
Thank you for offering up the suggestion! Let me know if I can check anything else.
154140
 
1 - 10 of 10 Posts
Top