Is my HG going south ?

[Mellemel]

I am thinking I am facing a HG job ! What do you think ? Last week was -25c for two days, then up to +8c the following day, I started the 4Rnr on the warmer day and it began with a short 5-second misfire then ran perfect. I thought possibly something had got damp in it from the big temperature swing. Each morning I had the same misfire, not much coolant loss, however, there is a small leak on the bottom hose from the water pump maybe accounting for the loss.
I disconnected the battery to re-set the ECU over the weekend and the misfire has gone. I see today inside the oil cap there is a mayonnaise residue, nothing on the dipstick though. Is this the coolant mixed with the engine oil or could it be a damp/moisture issue in the cap ? The coolant has no bubbling in the reservoir and the coolant in the rad looks clean.

What's going on guys ? She is 20 years old and has 395,000 km's or 245,000 miles, could be time I s'pose.

There is no loss in power, but the mpg has taken a big hit over the last few months, but possibly due to the winter !

 

[FROGrunner]

I would do a compression check on all cylinders first.

 

[reelamin]

Search this up...tons of threads and information matching your exact situation with outcomes including many other scenarios. Use any of your information pieces and lists of threads will show up. I hope it is not a HG only condensation.

 

[alumarine]

Most often a funky oil cap means condensation.
What kind of driving do you do?
Short trips in cold weather will make it worse.
Getting it good and hot for an hour or so will help get rid of it.

 

[Jt2El46]

I just went through the injector issues.You will get differing misfire codes but in the end it is an injector gone bad. That is also about the right miles to pull all of them and have them and have a place like RC engineering. 245000 miles is in my experience when the injectors start to leak and stick to the point of misfires and bad economy. I have had marginal outcomes with the remans off ebay. The best results are form cleaning and balancing the original DENSO injectors.

 

[Mellemel]

I think the condensation scenario is what I have had. Today the milky residue has gone. Temps are -5c ish. I only drive 20 mins to work at most it's only like 15 miles, I need to drive farther and warm her up better eh !
Misfire has gone too. I put in two bottles of Wynn's injector cleaner maybe that helped. HG scare subsided.
I read on the Yotatech forum someone had the milky residue in the oil cap on all his Toyotas, HG was fine. It had to be the wacky temperature differences I experienced last week. -25c to +8c overnight !!

 

[Mellemel]

How and where would I get the injectors balanced ?

 

[Jt2El46]

RC engineering is a place I have used for years, but there are several places. I have had good experience RC and they are fast. I through the injectors in the small USPS fit it ships box and I have them back inside of a week. It run about 25 an injector. They also offer and cali refit where they can increase you injector to specific cc per hour you want.

 

[19963.4lsr5]

I agree it's condensation not being burned off. It's happened to me on occasion with repeated short trips this time of year.


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[Renegade_Medic]

I'd vote for condensation as well.
Is there a lot of water and steam coming out of the exhaust immediately on start up?
Also there would more than likely be coolant mixed with the oil, making it nasty. "Mayo" under the cap can easily happen from cold, short trips in humid areas. I'd clean it off, maybe change the PCV (Haha, good luck with that), and go on a long highway drive to get it warmed up. 245k miles shouldn't be much on these.

 

[Mellemel]

Thanks guys, yup I am pretty sure it's a condensation thing. I replaced the lower radiator hose today and after draining the coolant into a large bucket there was ZERO oil in there. They definitely have not mixed, so no blown HG. Yippee.

Yes, there is a lot of water and steam first start up. The PCV was changed about 2 years ago.

 

[frodiesel]

How about your valve covers leaking into your spark tube, causing intermittent spark?

Not sure how you are connecting the dots from oil cap to headgasket without doing a compression test. Dont let fear control your life man!!

When was the last time you did a tuneup? Pull those spark plug boots, buddy. Inspection time to quelch those vampish fears.

Also, headgaskets can fail and NOT mix oil and water. If you get an aluminum head too hot it will warp and not hold compression, but will not necessarily mix oil n water.

 

[trailbikerider]

I used to have an old '97 Tacoma 3.4 that did this exact same thing in the winter on cold startup. I always thought it was a head gasket issue since my buddy (the previous owner) replaced the head gaskets once already but never had the heads resurfaced. -_-

Good to hear that's not what your issue is.