Diagnosing a clogged radiator

[unDummy]

Nissans don't burp too well. Several heats cycles are needed. Make sure the recovery bottle is full. When filling, hold the bleeder open until a steady streams exits the bleeder. This should only be done when cold.

What brand thermostat was used?
What year Maxima?

Clogged radiator depends on water used, maintenance interval, coolant used, and flushing method.

 

[MaximaGuy]

Thanks Dave H. I will heat up the car with the cap off and check the flow.

FYI, I just took the car to my trusted mechanic and he told me 1/2 Q worth of coolant was burped off the system (which I find hard to believe, since I have burped the **** out of it before taking it to him). I was also billed $95 for burping, if I had pitched in a little more I could have had a new radiator for installation.

Anyway, I drove the car back home and on highway uphill the gauge did go up again and now I have to take it back to him.

In short, these cooling systems are beyond my ability to comprehend and I am about to give up... last try if the mechanic fails to solve the problem, just put in a new radiator. I see no harm in replacing it anyway than spend another $100 for diagnosis by the stealership.

 

[MaximaGuy]

Papa Bear: Sorry didn't read your earlier post, anyway this is how it all started.

During the heat wave in CA a month ago my analog coolant temperature gauge moved up beyond the 3/4 mark but only during uphill drives.

I was due for a flush, so drained the old coolant and since it was due to replace the hoses (>100K on original hoses), I went ahead and replaced it during the flush.

Now after that too the temp used to shoot up, then I went ahead and replaced with OEM thermostat. This didn't help too, so took it to the mechanic and his conclusion was there was air in the closed loop system. Therefore he burped it running the car with the radiator cap off for 45 min, this removed all remaining air (this is what he told me). The whole system was thoroughly pressure checked for leaks and hot spots (clogs) in the radiator.

Now, that too hasn't helped and I am getting tired off my car and all the expenses I have put in to fix the problem. Following on what Dave H said, my last choice is the radiator, that alone hasn't been changed with the pump. Starting with a new radiator should hopefully put an end to my agony.

 

[stepside]

This sounds like a problem I had in a '94 Dodge Caravan. I tried all the fixes you mentioned and nothing worked. Finally I took off the serpentine belt and used steel wool to rough up the water pump pulley and all other pulleys where the belt runs on the back side. Apparently after a lot of miles the pulleys get very smooth and shiny and the belt slips under heavy load. It was a simple fix and the overheating problems stopped immediately. Hope this helps.

 

[labman]

Be careful. I have had coolant spew everywhere when the thermostat opened. wouldn't get my face over the open cap.

 

[Papa Bear]

Did these problems start BEFORE or AFTER your thermostat/hose replacement ??
Why did you change your thermostat in the first place ??

P.B.

 

[acewiza]

The easiest way to determine the condition of the radiator is to just look inside for scale and other deposits. Failing that, a close second is to pull off the bottom hose, stick a garden hose in the top and turn it on. It is probably OK if it flows without backing up. How much it flows (or not, as the case may be) will give you a ballpark idea of the core's inside condition.

 

[unDummy]

Is the rad cap new? If not, replace it.

Are the radiator fans cycling? High speed? low speed? relays? temp sensor for ECU OK? temp sensor for dash gauge OK?

If your mech or dealer can't figure it out, go somewhere else.

A UOA should be done to make sure that there is no trace of coolant in the oil.

 

[MaximaGuy]

OK, after numerous analysis and $, it is determined to be a partially clogged radiator.

I have ordered a new one and shall keep you posted, if the problem "ever" does get fixed.

Dave H was right it most probably is the radiator.

 

[MaximaGuy]

I replaced my OEM radiator as it was actually clogged. Replacement radiator was Cryomax (Made in Taiwan), the fit was exact to the OEM one. Overheating stopped in its tracks, I am happy that it is resolved. What I also realized was how much presurized the hoses were and little overflow into the overflow tank (meaning smooth flow from top to bottom with no blockage resulting in coolant entering the overflow tank).

Anyway, thanks to Dave H for his timily response that it would be the radiator that was causing the problem.

 

[esteve]

An earlier poster mentioned using an infrared thermometer to diagnose a clogged radiator and that's the way to go. I ran into the same problem in my mom's Maxima a few days ago and the infrared thermometer showed temperature differences of 70-80 degrees along the surface of the radiator. I had changed the thermostat which didn't fix the problem and everything else checked out (fans, relays, temp sensors, etc) so I became suspicious of the radiator. Sure enough, it was plugged up worse than someone with constipation.

 

[MaximaGuy]

esteve : How old was your maxima? I read thro the maxima.org forum and could not find one case of clogged radiators, I am suspecting my religious flushes has stirred things up.

I have put in Dexcool in it now with the new radiator and keeping my hands off the cooling system for another 3-4 years (this is the directive from my wife). I know my buddies with all kinds of vehicles and don't do anything for the cooling system and it runs like a gem for them for many many years, including my brother-in-law, he ran his Honda Acccord for 8 years with touching it....

 

[esteve]

MaximaGuy- My mom's Maxima is an '87. Strangely enough, I switched it over to Dex-Cool several years ago and found out later that there have been some issues associated with its use.

I don't mean to alarm you since you just put it in, but try a google search and there's lots of stuff that comes up although alot of it is just opinion and nothing concrete. In my mom's car, neglect (infrequent coolant changes) was the main culprit and I can't really blame the coolant. Also, I added some Bar's stop leak when the radiator was seeping a bit which I'm sure didn't help any.

 

[Papa Bear]

What was clogging the radiator ?? Rust, dirt, gel ??
I don't know, but I find it hard to believe that a radiator is plugged on a car that is serviced regularly. I have a '93 Accord and a '98 Corolla that have been somewhat ignored as far as coolant replacement and they both work great. Remove the rad cap and look in .. clean as a whistle.
Please let us know what was inside your rad that was causing restricted flow.

 

[esteve]

It looked like deposits and rust/corrosion were clogging up mine. I looked inside the filler neck and radiator hose tubes and there was quite a bit of gunk in there.

Like I said, my cooling system was neglected. Probably 2 coolant changes in 20 years plus adding stop leak for a leaky radiator took its toll. I did use Dex-Cool which some say increases those problems. It was a rusty brown color.

I also noticed a couple of strange things when I was trying to figure out what was wrong. The upper radiator hose began to balloon to the point it looked like it might pop. Also, when I drained the coolant it was coming out very slowly even with the radiator cap off. The car now runs rock steady in the middle of the temp gauge.

 

[Papa Bear]

Thanks, esteve, I was actually addressing my question to MaximaGuy.

 

[MaximaGuy]

I looked thro the radiator and I could see a white scaly stuff and it was falling apart from the bottom hole. I put my finger in and tried gettin some of it on my finger, I did actually touch it and it was like chauk mixed with water.

I did run my water hose into the radiator fill hole and water would overflow from the upper hole quickly. There seems to be something in it that was not making the flow even from top to bottom.

 

[sky jumper]

maxguy - I'm interested in this and would like to know more. there's got to be a reason it clogged - your car is too new for such a failure.

1)what type of coolant did you use for your flushes. I know you mentioned Peak Global, but what did you use before?

2)did you do full flushes? (e.g. drain, fill w/ h20, heat cycle, repeat until clear water drains out). or did you just do drain/fill with 50/50 mix?

3) if you did heat cycle, did you have your heater on during the process?

i suspect either you mixed uncompatible coolant types, or you didn't purge the air from the system in one of your previous flushes. some coolants do not react well when mixed with air, and that could've caused the corrossion.

My Nissan factory service manual defines a process of keeping the radiator cap off until the car heat cycles at least once (spewing coolant out the rad neck in the process) - then capping it and heat cycling 2 more times. did you do this?

also, not to make things more complicated, but if it were my car I would not leave that DexCool in there. I think that is one coolant chemistry in particular that is sensitive to air. Ray H may be able to confirm this. I would put the OEM stuff in and leave it in for 30k drain/fills. not worth saving $10 over the course of 30k miles on non-OEM coolant.

 

[MaximaGuy]

sky jumper: This is how my flushes have been, with now the odometer showing 110K.

1) At 60K miles, drained radiator and replaced it with Preston 50/50 coolant. Did not bleed the system of air.
2) At 80K miles flushed it with Peak Long Life (amber color) coolant. Did not bleed the system completely of air as desribed by you, just removed the air -relief valve and thats it.
3) At 105K miles, flushed with Peak (green one incidently is the wrong one to put on a maxima) Anti-freeze since my local Autozone told me they have removed all OAT/HOAT Peak coolants off their shelves.
4) I spoke to a Peak representative and will be switching to Peak Long Life (amber one I used earlier).

Now, comes to the question why not just use OEM. I am off the kind to give other coolants the benefit of doubt. Now, after spending some months on the coolant section, I understand that Japanese coolants are very high quality and there are very few American replacement fluids for them.

On hindsight I may have been an idiot to monkey with these coolants, I think a flush with the Peak Long Life (no silicates/phosphates) over the weekend should complete my expensive learning curve.

 

[sky jumper]

so the stuff you put in at 105k was the traditional green silicated stuff? (aka green snot of death) I'm betting that's the culprit. expensive lesson to learn, but look at the bright side - you now know more about coolants and radiator flushes than most professional mechanics.