I recently did a timing chain on my 1990 Toyota pickup (the right side guide had exploded) and I now seem to have a slight coolant leak. When the engine is hot the coolant level in the reservoir seems to be the same (I check before I leave and when I get to my destination) but when the truck sits overnight the coolant in the reservoir goes down by 1 to 3 inches. I have put a cardboard box under the truck and didn't see any drips of coolant on the cardboard. I have put in almost 3 gallons of coolant since I finished on December 30th. I do have an aftermarket radiator so the coolant capacity would have changed some but not by that much. does anyone have any suggestions as to where the coolant is going?

 

How's the oil level?
Assuming you don't have air pockets still in the system, Either it'd being burned in the combustion or you have a hole letting it into the oil.
Timing chains that ran long enough with broken guides will eventually wear a hole through the cover and into a water jacket, letting coolant drain into the oil pan.

If you get the engine warm enough to open the thermostat and get water circulating, and you gently squeeze the upper radiator hose, you'll feel the air bubbles as they pass by.

 

I did a whole bunch of research before I ended up replacing any parts and one of the things that I replaced was the cover as far as the oil level goes it seems within normal range when I checked it this morning I will be getting an oil change today anyways because it's that time so I will make sure I specifically ask if the oil looks like there's any coolant in it. Are there any hoses that are notorious for getting pinhole leaks? If so would a coolant pressure tester help finding the leaks

 

Radiator pressure test would be good, and a block test wouldn't hurt, either. Both tools should be available at the chain parts store loaner program. the block test uses a blue dye, which you might have tom purchase. No test is a bad test. either you're made aware of an issue, or you can cross one off the list. Both are good.

I assume you're filling the coolant bottle to the fill line when the engine is cold, and no more. i tend to run straight coolant in the overflow bottle, not 50/50.

 

When I originally filled the radiator out I was running a roughly 45 60 mix since I live in California currently and it doesn't get cold enough to require a true 50/50 unfortunately as I've put in almost an additional gallon of distilled water that mixture is going to be somewhat off. Once I figure out where this leak is at and fix it and then I will probably partially drain the radiator and fill it with more 50/50

 

You did pull the head and put a new headgasket on I hope?

 

QUOTE=Jimkola;52491961]You did pull the head and put a new headgasket on I hope?[/QUOTE]
Yes I did do that I ended up going with a OEM head gasket from 22RE performance. I also just got an oil change mechanic said that there was no symptoms of coolant in the oil

 

I am currently waiting on the pressure tester to be delivered tomorrow but In the meantime I plan on doing a cylinder compression check and see what that yields

 

If it's going out the tail pipe, code for bad oxygen sensor will happen sooner or later.

 

this post is going to be a little bit lengthy and possibly is going to be a little bit hard to follow but bear with me

I did the compression check yesterday and here are the results

cylinder 1: 148 PSI no added oil, with oil added 151 PSI

cylinder 2: 150 PSI no added oil, with oil added 155 PSI

cylinder 3 125 PSI no added oil, with oil added 130 PSI

cylinder 4 120 PSI no added oil, with oil added 125 PSI
I know there are three reasons why the cylinder pressure in 3 and 4 be so low. one the Rings are worn out two a valve is sticking open a little bit reason three is the one I hope is correct because it's a simple fix And that is one of the head bolts is not torqued down enough. The reason why I mentioned a head bolt not being torqued down enough is because when I was taking the head off of the engine one of the head bolts ( as it just so happens between cylinders 3 and 4) was very difficult to remove and when I finally did remove it it brought a bunch of dark gray powder with it. before putting anything back together and make sure that I cleaned out the hole as best as possible between filling the hole with some oil to break anything up, a vacuum to suck up all of the powder/oil available, and an air compressor to blow anything else out. but when putting that head bolt back in it was still somewhat difficult to get it thread in (it's not cross threaded) I know that it's just that stuff was shoved into threads so much that the bolt had a hard time cutting away the old powder.

this is the bolt
So my question is could this be where the coolant is leaking from into the cylinder head and if so how should I go about fixing it? should I remove the bolt completely clean it and put it back in or should I just continue to torque it down I would also like to point out that there has been no white smoke coming out of the tailpipe at any given time

 

I forgot to add this earlier but I plan to verify that it's the head gasket not being tight enough with the coolant pressure tester it has not arrived yet but I should have an update by tomorrow night (PST) at the latest

 

I never saw white smoke coming out of my tailpipe either. But coolant was slowly trickling out of the tailpipe. Oxygen sensor code light was coming on and going off randomly, and then just just stayed on.

 

What did you end up doing to fix it? I'd rather not pull the head again seeing as how it's a brand new head gasket and I don't have time or money to pull it again

 

I replaced the head gasket. It had a bad spot between cylinder number three and four on the exhaust side. Also, I installed a timing kit because of chain slap on start up. Timing cover was changed too because of chain grooves in the cover. I did use new head bolts.

I was losing coolant slowly round about six months or more. Just adding an ounce or two every week or so. Start up chain slap was getting worse, so I tore it all down, and fixed it all at one time. Oxygen sensor was coolant contaminated.

The Toyota head gasket should not need a re-torque...mine did not. Personally, I would re-torque the head bolts, and hope for the best. Good luck!

 

Thanks for the info. Do you have any suggestions as to what I should do with the head bolt that is difficult to turn I suspect that this one head bolt the I suspect is the cause of my problems I don't want to keep torquing it and have it break. Is it possible to just pull out the one head bolt that is having issues clean it and the hole as best as possible and put it back in? Or would that cause further damage

 

I wonder if anyone here has ever run a tap with the head and valve train in place?
Ideally a thread chaser, but those usually have a bigger head for a socket. you might need to use a regular tap, along with an extension that has some sort of allen screw to lock it in.
I have a spare valve train, I'll mess with mine and see if it'll fit

 

I would imagine that a tap would go through the valve train and head just fine since the whole for the bolt is much larger than threads. my only question is how would you manage to extend the tap enough to actually get all the way down in there
It might actually be better to use an old head bolt and cut a notch in the bottom since the head bolt is long enough. Luckily for me when I reinstalled at the head I made sure to use brand new bolts like the service manual recommends

 

Extensions that are thin, and have allen screws to lock in the bit are readily available for drill bits. Problem is, most of those are for hex-shaped, and taps usually have a square head. Thread chasers take hex, but are typically pretty big. That's why i was hoping someone here has already done this, and get their input.

 

Maybe it would be beneficial to just make a thread chaser that's the right size just cut off where the hex is and ask someone who knows how to weld to weld it to a long socket extension or even one of the old head bolts

 

I took my Snap-On 12mmx1.25 tap and was able to insert it into a 9mm 6-point socket. The four corners of the tap fit pretty snug into the hex configuration of the socket. I then inserted it into the bolt hole on the valve tower. It makes it with barely enough room to spare.

You now just have to figure out how to hold everything together. Silicone adhesive(not caulk) for the tap? Thin 3M packing tape for the socket and extension? You'll have to be pretty careful when you start the tap, you just wanna chase threads, not make new ones.