bjr

2005 with 265,000 miles.
Waited first time to drain coolant at 60,000. Then every fall since then I drain and fill with new every year. Never a flush just drain and fill. October 2015 in addition I bought the whole Z1 silicone hose set and a new thermostat just because of age. The hoses didn't fit properly so I did the thermostat and upper, lower and the small hose by the thermostat with stuff from Autozone and Nissan dealer.
I mention that because my recent high temperature problem could have to do with needing to burp the system properly because replacing the thermostat makes it more difficult than I am used to doing every year.

I've tried burping it with spill free funnel and all methods involving squeezing hoses and the bleeder screw by the firewall, running at 3000rmp etc. Gave up and drained it to start over but ultimately that did not help.

After the car warms up and it is in the 80s or 90s outside at random after 10-30 minutes of in town driving it will go well beyond the normal 40% mark. Some days it can handle it and goes up and down between 40-60% fine if I just keep an eye on it. Other days it will not go down below the 75% I let it get up to unless I turn the heater on and keep moving. At first I thought it was only if the A/c was on and I am not moving but have seen it also happen around 40-50mph with the A/c on! Never had a problem on the highway going 80mph.

I know this can be a lot of things but I have two questions before I am willing to throw money at a new radiator.

I have bled it several times both before the recent drain and refill and after. A co-worker had such a big air pocket in one system years ago that he drained it and started over and it solved his problem.

I have suspected from my symptoms (probably haven't listed them all here) that I had an air flow problem. I thought the fans might not be running all of the time but every time I have checked on them while it is overheating and have done the AutoTest procedure they both run at high and low speed reliably. With some other clues that have come up more recently (like problems at 40mph) it is probably a coolant flow problem anyway.

Pressure test on radiator has been done.

Borrowed the tool with the blue liquid to test for compression gasses at the filler neck. I know this is not a 100% definitive test but I passed it and don't suspect a head gasket issue.

Everything else checks out for proper thermostat function and other things that are recommended to check. Probably forgetting a few things I have done right this moment.

So...

If a system has been drained and filled every year can there still be blockage in the radiator? Where would the sediment come from? Things like the inside lining of the hose wearing down? The car acts like the radiator just cannot keep up with the A/c on. Since it is random and other things check out OK can the radiator be ready to fail from blockage or the core/tanks falling apart internally? Never owned anything this long to experience a "natural death" vs. neglect problems of sludge and rust.

Since the system is maintained I don't suspect anything wrong with the water pump but is there anything I can do to get a good feeling that it is not the water pump before I buy a radiator? The pump is the only thing I cannot test. Is there any way to inspect it with a borescope? It seems like there is enough plumbing near the pump that it may be possible to scope it but need to look into that more.

I intended this to be short but if anybody is willing to help it all needs to be brought up I guess. There are probably a few more things I could add that I am forgetting right now but would appreciate help further diagnosing the radiator or water pump specifically. We can skip all of the other stuff that gets brought up over and over again.

eZg

iTrader: (5)

are you refilling the rad fluid slowly...like the service manual says?

Have you searched for all the Burping 'Tricks'?

Was the Tstat Nissan brand? You post says both autozone and Nissan parts so wasn't sure.

good luck. my bet is air bubble

bjr

Yes. In October 2015 I just let it drizzle directly from the antifreeze bottle as slow as I could. When I did it recently I bought new drain pans at the dollar store and after I drained it all I used the extra one and drilled a #48 size hole in the bottom and let it drain in by dumping the other pans into that one. It took about 45 minutes to fill.
I've read over 20 posts on burping and never had trouble for the last 9 years. Of course this time had a Tstat change and that make it more difficult from what I hear.
I burped it with a spill free funnel on car ramps and squeezed the lower hose after the thermostat switched and then squeeze the cross flow hose and then the upper hose. Over and over until no bubbles. Let a few fan cycles go then hold it a 3,000 rpm for 15 seconds then squeeze all of the hoses again. I did this for three nights in a row for about an hour. The thing is that I always get a few more bubbles after the 3,000rpm hold. That's why I got the kit to test the head gasket because at some point those little bubbles maybe should go away 100%. But it could be turbulence from the water pump since the system is not closed with the funnel in there. Plus at this point the fluid is almost boiling too since there is no pressure on the system. So maybe I'll bleed it a few more times but I've exhausted that effort I thought.


I got Nissan Tstat. The z1 hoses not fitting left me with a car with no hoses to put back on so I tried to get Gates hoses at oreilly but couldn't get them the same day so my upper and lower hoses are from Autozone. All my other hoses right now are still 10 years old for the moment.

eZg

iTrader: (5)

Well certainly sounds like you know what you are doing.....

a couple guesses in hope of helping

Radiator cap??

Intermittent fan motor failing......isn't that a somewhat common failure?

good luck man

bjr

I forgot to menton that the pressure tester I borrowed was able to test the cap and it works perfect. It was new in October 2015 and is a Nissan cap.
I suspected the fans but they are always working very good when I check on them or test them. I bought two new motors but decided not to put them in yet since that does not seem to be the problem. If I get a new radiator I will put them in for sure.

Today I drove home on the highway. I turned on the a/c at work, drive 3 miles to the highway and drove very fast for 20 miles no problem. Within 30 seconds of getting into town the gauge was climbing. I turned off the a/c and it wouldn't come down like I wanted so I ran the heat the last 5 miles home and it was fine that whole time. It is 90 degrees today.

I am going to bleed it once more after dinner. I will leave the car level and see if I can add any fluid by just opening the bleed valve by the firewall. Then I don't know if I should try the funnel again with the goal of having no bubbles after reving to 3000 rpm or if I will try the FSM method with the cap closed and waiting for the car to cool off in between. I would think driving it for two weeks and checking the level has been the same as what the manual suggests in the same basic way - run, shut off and cool, check and fill, run again. Repeat three times or more.
Sucks not being able to easily test the radiator or the water pump because I could agree its still a very small chance its an air bubble.

bjr

I was able to pour in at least one ounce into the bleeder by the firewall. I followed the FSM and warmed it up at 3000. I had to let it cool for over two hours with a fan in this heat to get it down to 122 degrees. Luckily the level did not drop so I could move onto the steps of running idle to 3000 over and over with the heater temperature in every position several times. I guess reving the engine along with the heater **** adjusting is a little different than the funnel methods or just driving it hard all week. We'll see what happens tomorrow. It is going to be hotter than today.

eZg

iTrader: (5)

Any progress??

As much as you have done...I would think if it WAS just a few air bubbles. Those would work themselves out after a few days of normal driving.

bjr

I sure hope that it would fix the last few bubbles too. That's the way I understand it.

Anyway, Thursday night on the way home it did it again so after reading your replies and thinking I had nothing else to do until the weekend when I might consider picking up the radiator I ordered I decided to bleed it again.

I only started this thread because I have been having this problem for a month and have bled it about 3 times before I drained it to start over and about 3-4 times after. All about 1 hour sessions until there were either no bubbles or just a few small ones you could count. I've read over 20 threads on this and also read many things out on the outside world other than here. I was sure I was done bleeding and also performed other tests and wanted to know how to evaluate the radiator and water pump without guessing.

Well Thursday night I bled for 2 hours and 45 minutes. During the second hour I didn't think the bubbles would ever end but they did. I got it to the point that no new bubbles formed when idling for two fan cycles and then squeeze the upper hose. After holding at 3000 rpm for 10 seconds then squeezing the hose again, the first time had no bubbles, the second just literally 6-10 bubbles then the third time none. It was 10:00pm and 102deg in my garage so that was it for me. It felt like I got it.

Drove to work Friday with A/C on but it's 71deg outside. Went home my normal test route where it will overheat eventually but there is not much traffic so that I don't stand still often and I can pull off anywhere if I need to shut the car off. It did fine but it was only 82 degrees. Stopped at home for 15 minutes. Went to dinner 5 miles away. Stopped 30 minutes for dinner. Headed for the next town over. Got half way there and it starts overheating. And it won't cool down even with the heat on. I pulled over and shut it down for 30 minutes then drove it back home.

I tried bleeding it again and there were some bubbles at first then a lot for a few minutes then they quickly bled out again. What puzzles me after about an hour though of keep trying to make sure at some point if the fans run at 208deg isn't it possible I will see a few bubbles at random because the coolant is not under pressure with the funnel method and I am at nearly the boiling point? Some part of the coolant passage must be much closer to 212 and be starting to boil? I can never get it to stop 100% bubble free! Thursday night seemed like I got a lot out of it though that maybe I missed

So I still need to figure out flow from the pump and flow of air across the core. I'm thinking about getting some clear tube to put in place of the upper hose to see what kind of flow I get. I also have a home made smoke machine I want to blow some smoke in the bumper grille and see what the fans can pull through. If I have too many damaged fins though, they are going to be on the A/C condenser and a new radiator may not fix that.


I made an attempt to determine the difference in temperature between the inlet and outlet of the radiator but that turned out to be a disaster. I feel like the engine block and the fans blowing on the lower hose eventually raise the temperature of the hose and using an IR temp. gun to determine the temperatures is not the right idea. At first it seemed ok as things warmed up but eventually the lower hose was hotter than the top. For the first 10-15 minutes everything seemed like it should even after the Tsat opened and the fans went through a couple of cycles. Then I think other things were working against me getting good readings because that area just gets to hot to be using a temperature gun reliably.

I hope somebody has better ideas than my last couple I'm going to try

eZg

iTrader: (5)

That sounds like it F'ing sucked.

those bubbles could just be turbulence in the system.

I don't rem if you have ruled the fans out. I wonder if you can check voltage to each fan motor. But even if you determine that......then how can you make sure the fan itself is performing as it should? The OEM motors are kinda expensive to just guess at.

I went with 2 spals and customized a aluminum shroud from Amazon. I tried to wire with each it's own relay but ended up having to use the stock harness.....less than ideal.

dboyzalter

iTrader: (3)

After 265k miles and replacing the coolant yourself since 60k miles I would say that your probably the expert resource on the coolant system at this point...

Just an idea but could your water pump be crapping out on you from its old age? Last one I changed on a car with 196k miles and it still looked good, but they do get damaged sometimes...

bjr

#1 on the fans - I think they are OK unless they are starting to drag and only putting out 80-90% of rated rpm. I guess I should check with an ammeter if they are pulling too much current. I already bought TYC replacements from Ebay for $87 shipped total for two. They got good reviews but since I have to take everything out I was trying to make sure it wasn't something else. Every time I'm overheating it looks and sounds like both fans are blazing away! You can hear high speed inside the car with the windows down.

There is also a self test and it passes every time I try it. There is a trick with your keys and door switch to get your headlights, horn, wipers, A/C clutch, and low speed then high speed fans to all cycle three times and the fans always work whether the car is cool or I just brought it home with it overheating and I run the self test in the garage after I turn the car off. They are always spinning high speed while I'm overheating away from home and I pull over too. That does not mean the new ones won't work better I guess.

#2 So we all might agree then as long as every time I check on bubbles a few are OK. Call it turbulence or else maybe close to boiling.
I can move on to the last couple of things I could check or rig up and after the big bleeding event Thursday night I'm done.


#3 everything I read on this water pump is that it is indestructible. I wouldn't expect the vanes to be corroded unless on one of my refills over the years that I got enough bubbles in there to cavitate and destroy it. Since I'm not weeping, mixing coolant and oil, or squealing the only thing left is worn out vanes but the system has been maintained. I replaced a few hoses last year and they were spotless inside. This is why I want to put a clear hose in the system to check for flow I guess.


I think that if we can't figure this out this week I might pay for that new radiator and take the old one out and try to flush it , scope it inside what I can with a camera snake and also try a crude flow test against the new one. Throw $200 at the problem and see what shakes out. My time is getting more valuable as this drags on. My luck is that it will not fix it though......

bjr

Seems as though I cannot easily find some tubing rated for the temperature without ordering something almost custom made in that size and waiting who knows how long for it. I might be able to get something at Home Depot to put in that is rated for 170deg but it hardly seems worth it now. I would rather spend some money on a flow gauge if I could find one.

I'm going to try calling a radiator shop in town that a co-worker recommended today and see what they could help with.

It is so random once the car has been running for awhile. It got too warm about 3 times on the way home. But it recovered immediately with the heat on. I was able to turn the A/c back on minutes later and keep driving in some of the same conditions as far as I could tell..

eZg

iTrader: (5)

Where you stopped in traffic when it got warm the three times?

bjr

This time yes. And almost every other time previous.

BUT - Before that lengthy 3 hour bleeding session there were a few other times it happened running at a constant 45-50mph though. There was also one time on the highway I was already running at least 80 and some people were trying to weave around traffic and I put the pedal to the floor a few times and temperatures started to climb even with that much air flow - that is assuming my fins aren't blocked.

If I had to guess, most events are either from sitting too long or too high of a load on the car. Somewhat random. Only constant is A/C on and hot outside.

bjr

Most of what one would need to know in one spot. Have not seen anything this comprehensive before. I need to review
http://www.tegger.com/hondafaq/overheating/


Tonight I am going to see if I can determine if anything external is clogged. That many miles must need some cleaning or fin straightening. I'm worried that I've overlooked there being two layers (a/c condenser and radiator). I've already seen if paper is drawn against the front with the fans on but will see if they draw smoke through every where and also put a bright light behind the fans. Need to see if I can see any light from the bumper side. Just keep plugging away on small stuff I missed that could matter until I get lucky I guess.
Also maybe if I can get the radiator and condenser separated but still hooked up I can feel for hot and cold spots while it warms up for the first few minutes?

tampa_joey

i've got an 05 121,000k miles, and during cooler weather on short runs, ran just fine, once weather warmed up, it ran fine unless i ran a lot of short trips in a row, or sitting in traffic
then i would see the temp needle move upwards, so, crank heat, and get moving, and temp would sloooowly drop back down.

anyhow- it turned out to be
1)the fans- they came on like they should, turned like they should-however- they had no ummph. once during testing the fans, the 2nd fan didnt turn on until flicked with a finger (or i would suppose- getting nudged by air flow while driving)

2) radiator cap wasnt holding pressure- a very slow leak.

after replacing the fans, i could hear the difference in the sound of the fans from the drivers seat as to what they sounded like prior to change.

perhaps you have gotten so used to the sound of the fans slowly slowing down you have gotten used to the sound?

bjr

Very happy you shared this. Maybe I will go ahead and put my new fan motors in. I hesitated because they came a couple of weeks ago and since I had a few more things I could check I didn't want to have to take the hoses out and start bleeding all over again. I was trying to catch my fans acting up once before doing it but I understand what you are saying about things only seeming correct.

bjr

Last night I pulled the bumper and straightened all of the a/c condenser fins and it either didn't help out or possibly helped just a little bit. It is very hot today and I was surprised that I was able to leave the a/c on most of the time but it still has the same old problem.

Since there were so many fins damaged I figured I would see if I can separate the radiator from the condenser to peek at the radiator fins but I think I would just waste an evening doing that. When I saw up close what I had glanced over with the fins I skipped the smoke test and just started straightening them. I didn't get any more light to shine through but don't see much chance of light shining all the way through so many layers with things all bent up. Probably not much light would shine thorough both layers brand new if the layers don't match up.
There were a lot completely fiolded over with zero chance for sure flow so I think at least most of them are breathing now through to the radiator.

Not sure what else it could be so since I thought it could be the fans before maybe it is them after all. Zero additional money spent and not a hard job to do. At least I've learned all the bleeding lessons I should need.

eZg

iTrader: (5)

Seems like that time it got hot on the highway might have been air bubble. Makes sense that it could MAINLY be an intermittent fan issue since it mostly happens in stop and go traffic. Mostly. (Aliens reference)

bjr

I sure think it could be. I believe that incident was before I bled it for 3 hours. Hopefully even though I knew it was difficult to bleed just couldn't comprehend how much trouble taking the tstat out could cause. I definitely got out a LOT more bubbles than a few left over from turbulence or near boiling that night. After the two hour mark I didn't think they would ever end once they finally started!

Also does make sense at 40mph when the fans still do need to run. The chart in the FSM shows they only aren't needed above 80mph(?) And that is only if the a/c system pressure is hihger or lower than some number. I couldn't figure out why it cared what the compressor system pressure was to run the fans at high mph.