Engine overheats, coolant level drops

that's a good question. i can't answer it with certainty but i guess that, if a gasket is blown, the air pumped in the cooling system would leak into the cylinder(s) that correspond to gasket breech but what i don't know is whether that's an airtight system or has a valve to bleed.

if it is NOT an air tight system, then it could be used as an indicator provided you're sure that the cooling system itself doesn't leak. if it is an air tight system, then it wouldn't matter because the pumping of the cooling system would just expand onto the cylinder system, unless there was some kind of valve or another way to bleed it.

but these are just speculations, i look forward to see better answers

 

Not usually, unless it's a major leak, but by then it's obvious anyway.

The 4.0 cooling system operates under 16lbs, and pressure testing is more to find a coolant leak than to diagnose a head gasket.

You'd have to pump the system up to about 150psi (about equal to what a cylinder will produce) in order to trace it, and that's way more then you'd want to pump into a sealed system that's not designed to handle it.

 

so, to summarize, there are 3 way to test for blown head gaskets, assuming that engine overheating has already been established:

1. Reach for the head gaskets physically -- the hardest way to do, you might as well replace them if you're there
2. Block testing
3. Traces of dyed coolant on the spark plug tips

Is this correct or are there more ?

 

that summary was added to this thread yesterday morning, please look for my post that has a picture of my OBDII attached, it should stand out.

and i just decided to actually go ahead and replace the head gaskets and pretty much all the other gaskets (valve cover, air intake, coolant intake etc). i am excited to lift the cylinder heads and the timing chain cover and do all that good stuff i never have before... because the truck is 120K mi and has never done before so i might as well + it will be a great learning experience

thanks

 

here is the deal... why not take it to the dealer and let them diagnose the problem? I get what you are doing, but your are throwing money at the problem. you might have replaced a water pump that was good for another 100k miles. You might have replaced a good thermostat. Now you are going to tear down an engine and replace a gasket that might be fine... And, if you don't do it right then you are really screwed. A second set of eyes, is what you need. if he says, yup its the head gasket, then roll with it. My .02

 

And we are off,

 

Because a new pump costs less than a dealer diagnosis.

Another reason is that I value learning experiences as one of my primary directives in life is to acquire as many skills (even being mediocre at most) as to minimize my dependence on hiring outside help. Self-reliant prepper kind of mentality.

So I actually like it when things break because that gives me an opportunity to learn how to fix them.

There are other reasons but these should suffice for now.

Thanks for checking in...

 

As long as you know that this job done improperly can end up costing you an engine replacement. I'll bet that is more expensive than a dealer Diagnosis. A lot more. If you are good with that, Go for it.

As for the below quoted statement and your posting history here. I see a lot of learning opportunities in your future.

 

being willing to make oneself look like a clueless moron and take risks has always put me at an advantage to pick people's brains and get ahead much faster than others who were more shy or risk averse. in career and life. worked very well so far. no major damage done. only success and sneers from those who see me as taking their job from them.

frankly, i see myself performing surgeries on people some day without ever going to a medical school.

 

The mods already had to clean this thread up once, next time they may not be nice enough to unlock it for OP.

If OP wants to handle this on his own we have to respect that. We've told this OP a few times that driving the truck while it was overheating could of had some consequences as well as letting him know that it wouldn't be a bad idea to seek additional diagnostic assistance. Pummeling him with reminders is just going to cause a situation.

 

this thread has been persistently sabotaged by people regurgitating non-technical advice from the beginning. i understand say it once but too many people have been cluttering a few useful advice here and there with unrelated garbage, like that moron posting Jack London novels and such...

or idiots who post emoticons with popcorn... adding nothing of value to the discussion. only burying useful advice in their flood of garbage, making it hard to find.

if it wasn't for them, this thread could have been 2-3 pages long, not 11

 

Just keep on keeping on . The less you indulge anyone who disagrees with you with the argument they are seeking the less likely this thread is to drive away others that are trying to help you.

 

^^^ Agreed. Welcome to the internet.

 

the format of a forum can encourage or discourage trolling. e.g. take a look at any stackexchange forums and you will see how it is virtually impossible to troll there -- there is a distinction between ANSWERS and COMMENTS and you can get upvoted and downvoted, contributing to your total reputation. while they do have http://mechanics.stackexchange.com/, there isn't one that is specific to Tacoma, so i post all my generic questions there and Tacoma-specific in this trollfest. stackexchange is much nicer to use and it is easier to tell good from bad answers and completely disregard comments

 

OP, I've read thru this entire thread but due to an advanced case of CRS, I can't remember if this link has been posted. It's chock full of good info and might help you now and in your future endeavors. Best of luck.

http://www.customtacos.com/tech.old/files/05FSM/repair.html

 

If you are going to change the Head gasket I highly suggest changing (not inspecting) the bolts on top of using a GOOD Torque wrench not something from Harbor Freight. The link above is Awesome!

 

^

I'm pretty sure if OP responds this thread is over. Too bad. I really wanted to see this thread have a good ending after the bruhaha about a week ago.

 

dont lock... I want to see what happens next!

 

1.) You are doing a good job there.

2.) Well fuck me! Frankly, I see a jail cell in your future. Dr Foampile.