And a normal working xj can force coolant out of fused plastic seams only when cold, yet open the rad cap right after and be fine? My mind may be slow here, but I can't make sense of it.

 

What do you mean open the radiator cap and be fine?

 

As it warms up coolant expands - then the excess goes into the barf bottle. When it cools down coolant shrinks, sucking it back from the bottle.
If it does not do that, it fills the bottle, but suck air in as it cools down. The barf bottle stays full all the time.

THE ONLY WAY TO STOP THAT IS FIX ALL THE LEAKS.

Air in the system causes the gauge to act strange - just like yours. You may think there's no air - but -.

 

Sounds like u may have some issues as well. Malfunctioning t-stat, air in the system, bad electrical connection. With regard to the t-stat, it shouldn't allow a big gulp of cool water to pass suddenly (unless it's sticking). Even then, coolant that leaves the radiator enters the block and is heated in the block well before passing thru the head and reaching a temp sending unit. A properly functioning t-stat opens very slowly/very gradually. Why would u block the rad if it reaches 210?

 

I mean I can take my radiator cap off and there is no pressure behind it. Does that mean that only sometimes the pressure will leave out the sides of the radiator instead of into the overflow bottle?

 

No matter how hot por cold the engine is - if the temp sensor isn't submerged in liquid, it will read cool. Air pockets passing by it drives it nuts!

ANY LEAK WILL SUCK AIR IN.

 

Air would cause it to overheat iirc, and the open cooling systems purge themselves. Even if a tiny leak did suck air in, I can't imagine it wouldn't get back out for either of us.

I have done multiple purges when I was having issues in the past, with the same result every time. No bubbles come out unless it was me that put the air there. Before it gets to operating temp and the tstat should open, it would constantly dump coolant at a fast rate, im sure about 300ml before it got to temp. with the cap off. I think the issue is more with the sending unit or connection for our low readings, possibly the tstat. Air still doesnt explain my history of leaking coolant out of the path of least resistance.

 

Fix the leaks!!!

 

Something has to be causing them in the first place! first the hcv and 2 loose clamps leaked from the bad cap. fixed those and then 2 more clamps leaked, so tightened the hell out of all my clamps and no leaks for over a month. Now the radiator is seeping from the seams! Something else is behind that obviously. If I replace the radiator, what will be the next weakest thing to go out? I could just keep blowing through radiators because the underlying issue is still there. Both sides of the radiator are leaking in the same way, that cant be a coincidence either.

No blow back from it leaking during driving, doesnt leak when the xj is running I dont think. Once it is shut off cold it then starts to drip.

 

You can throw more parts at it - cry all you want, ask for help all you want, ignore what we say, it's not going to be right until you fix ALL the leaks.


Air is much thinner than coolant - it can get through places coolant cannot.

The easy way to tell if it's sucking in air - the overflow bottle does not go down when it cools.

But if you like having trouble, don't fix it!

 

The HCVs are a POS and leak all the time. Hose clamps need tightening from time to time. Radiators that are old and have crimped-on plastic tanks leak over time. It ain't some big mystery!!!!

 

Did not mean to offend you, but your rant is worth nothing if you actually read the thread. I already stated my plan for my tstat/sending unit. It is causing no harm and was just a curiosity question. I have thrown $10 in heater hoses and a rad cap at my problem so far. I am running with ideas posted earlier in the thread but I ask questions to learn, not to disagree with what the person had to say, except yours because you obviously didn't read. I also stated that my coolant level in the overflow bottle does in fact rise and lower with the temp.

Everything has been fixed up until 6 hours ago when the NEW radiator leak came about and that is why I was posting. I plan on a new radiator when I get the time, but until then as stated above, hell yeah I am going to ask questions to figure out why.

Your use of "we" to associate yourself with everyone else would offend me if I was another person commenting on this thread.

 

I'll join rrich in the "we" corner. Unsubscribed.

 

Yeah forgot to mention here that the HCV was only a year old and was leaking out of the center where the metal arm would open or close the valve. I assumed since the radiator didnt leak when the cap went bad or when the hoses leaked, that there was still an issue besides just a junk rad.

I would love to think it was a coincidence that a 15+ year old vehicle with no cooling problems in at least 6 years would have every single connection and weak spots leak within 3 months of each other, but I still question why.

 

There's no coincidence that a 15+ year old vehicle of any kind doesn't need constant maintenance to continue to be a reliable DD. If it's broke or leaks.....don't question it, fix it, or be prepared to walk..