Do radiators get inefficient simply due to age? (1 Viewer)

[BullElk]

I'm curious if radiator in my '06 LX could be less efficient in cooling under stress simply due to age. I mean there is obvious nothing mechanical that can wear out like other parts.

No leaks, water pump works, everything seems to work perfectly and heats up to the normal 195* when idling in summer. The only issue is that it will get to 215* pretty quickly when pulling an empty trailer going 75-80 mph at 2500-2800 rpm. If I get back down to 65-70 at 2200 rpm it will cool down to 200*.

I realize my '99 LC is designed to idle cooler but it still doesn't increase temps so rapidly like the '06 LX. The '99 has a newer radiator and it appears the '06 LX radiator is original with 256K miles. Wondering if the cooling efficiency simply decreases with time.

Thanks.

 

[cmck]

I'm curious if radiator in my '06 LX could be less efficient in cooling under stress simply due to age. I mean there is obvious nothing mechanical that can wear out like other parts.

No leaks, water pump works, everything seems to work perfectly and heats up to the normal 195* when idling in summer. The only issue is that it will get to 215* pretty quickly when pulling an empty trailer going 75-80 mph at 2500-2800 rpm. If I get back down to 65-70 at 2200 rpm it will cool down to 200*.

I realize my '99 LC is designed to idle cooler but it still doesn't increase temps so rapidly like the '06 LX. The '99 has a newer radiator and it appears the '06 LX radiator is original with 256K miles. Wondering if the cooling efficiency simply decreases with time.

Thanks.

I have a 99 and I would say there is no mechanical change over time in a heat exchanger. The main factors is a change would be how much water is flowing (water pump) and when (thermostat) and any build up of material in the fluid channels.

I use the Toyota red fluid and it is very clean inside (that I can see). I have not flushed it. I have replaced the water pump when the timing belt is done every 90k.

 

[abuck99]

Yes.

Coolant looses its efficiency, as does waterpump, thermostat and radiator if not flushed periodically & will start to get internal build up, equally important the external cooling fins (both sides) should be cleaned periodically- condenser, radiator, oil cooler.

Based on your feedback of pulling trailer- and speed related temp increase, fan clutch could be slipping too much under load. If your fan clutch has never been replaced or the fan clutch oil hasnt been replaced; it might be warning that its loosing efficiency.

 

[toyotaspeed90]

The main factor would actually be if there is dirt/material build up on the outside of the radiator (jammed in the fins) causing the radiator to not be abltle to dissipate heat.

 

[liveoak]

regardless, you should replace the radiator if you have 256k on it. You're just asking for trouble. At that time, you should replace upper/ lower hoses, thermostat, heater tees and hoses. Refill with Toyota pink only. If you haven't done the timing belt, this would be a good time also. I have some part numbers here
Timing Belt for Dummies writeup

 

[BullElk]

Timing belt, water pump, heater Ts ,etc are new. Rad, condensor, tranny cooler are cleaned regularly.

Fan clutch oil has not been replaced. I usually do that when there is no spinning resistance in fan. It seems to spin properly now. But I may need to replace fluid anyway.

 

[2001LC]

A radiator at those miles may or may not have internal build up. It depends in a large part to if properly maintained from mile 1. If not you may be able to see build up on core just by looking in radiator through top (cap). Any build up seen from top and you can bet there is much more unseen within. The fan clutch could easily be weak. Don't overlook drive belt tensioner and drive belt.

You'll also want to watch fuel trims. Running at 189 jumping to 212 rapidity, can very easily be caused by engine running lean.

 

[jerryb]

Is there such a thing as inert fluid running through a metal pipe and not causing flow or wall degradation?

Everything on a car degrades, is that a good answer? Oxygen is toxic.

 

[liveoak]

Rad, condensor, tranny cooler are cleaned regularly.

we are talking about a plastic radiator with 256k. the plastic degrades no matter how well you clean them. you are driving a ticking time bomb. I have personally witnessed 2 cruiser radiators and a jeep blow the top plastic tank because of age and miles.
Here's a good example




here is my buddy's jeep radiator, also on the mojave rd trail, same issue

 

[BullElk]

You'll also want to watch fuel trims. Running at 189 jumping to 212 rapidity, can very easily be caused by engine running lean.

I also get a P0430 code intermittently. Could this be what you are referrring to....running lean and perhaps causing the quick jump in temp?

Thanks

 

[2001LC]

You'd need to watch fuel trims.
The RH CAT may be clogging. Engine loads up due to restricted exhaust. Which could also be a cause for temp jumping rapidly.
You say "intermittently" Is P0430 clearing itself?
Is this the 06 w/260K?
Does this engine ever stall?

 

[BullElk]

The CEL will come on for a few days and clear itself. Then a week or so later come on again.

Yes, '06 LX with 260k.

Engine never stalls or does anything abnormal other than temperature issue. And that is only when running 75+mph. It always idles at 195* with A/C running is hot weather.

 

[nissanh]

The channels inside the radiator can get clogged over time.

 

[2001LC]

Sorry for getting off topic.

Air fuel mixture lean (low fuel to high air mixture) and cylinder heads run hot. Rich condition they run cooler. The response in engine temp is fast. Whereas coolant issues themselves tend to be a little slower to change temp read out up or down.

The ECU, test CAT at 2K to 3K RPM in 5th gear. Running at HWY speeds is best thing we can do for CATS, it cleans them (cooks them, like turning oven to self clean). Could be as it comes up to test parameters, it fails. Then as your continue driving on HWY at higher RPMs, it cleans out the clog.

I asked about coolant loss? as coolant can clog CATs. So can oil!

My next step would be to check compression.
At which time take a good look at coils, boots and spark plugs.
At same time I'd take care of any vacuum leaks.
Also inspect for exhaust leaks pre CAT as main area of concern.

For some reason I'm finding bad fuel pumps in 06-07 with bad CAT codes. I do not have a good reason why. As a lean condition does not generally clog a CAT.

 

[BullElk]

Good info. Thanks

Can't confirm any coolant loss. If there is, it is too small to recognize. What is interesting to me is how fast the engine temp can go from 200 to 215ish as soon as accelerate from 70 to 75. Then temp drops just as quick decreasing back to 70. I wonder if the thermostat isn't opening and staying open efficiently enough as required when engine works a bit harder. Probably should change it anyway.

 

[flintknapper]

I wonder if the thermostat isn't opening and staying open efficiently enough as required when engine works a bit harder. Probably should change it anyway.

That's where I'd be looking. The T-stat on my Wife's LX failed (completely closed) about 1 month after being installed (new Toyota part).

 

[BullElk]

Isn't the Tstat for an '06 different from the older models in that it is 195 degrees instead of the older 185 degrees? I'm only finding the 185 degree Tstat with part number
Toyota 90916-03100

 

[blatant]

0430 is a start with new gas cap code, isn't it? If your cap has equal miles, the gasket will feel like hard plastic, should be soft. Cheap start, and likely needed either way.

 

[2001LC]

Isn't the Tstat for an '06 different from the older models in that it is 195 degrees instead of the older 185 degrees? I'm only finding the 185 degree Tstat with part number
Toyota 90916-03100

According to FSM they are all (98-07) 82C (179.6F) thermostats. We do have two different PN #. The newer for VVT 06-07 is 90916-03138 which is near twice the cost. This could be because due to environmental guidelines to remove pollutants in the manufacture processes.

Where did you see these two different temperatures of 195F & 185F?

I replace a lot of thermostats and rad caps these days. In the passed, I did test many thermostats in boiling water. To see that they begin opening at 80-84c (176-183F) and that valve open 10mm or more at 95C (203F). I found them all to be weak (not opening 10mm and/or opening early). So anymore I just replace with T-belt job, over ~90K miles or radiator replacement.

I also clean a lot of radiator fins these days.

Radiator fins need cleaning! Alert Alert Alert

I've a 06LC w/192K I just bought. In reading history I found PO complained of engine temp raising when both front and rear AC on. Toyota Dealership diagnosed with clogged radiator fins. Recommended new OEM radiator, $600 for the US spec Radaitor plus coolant and labor. They should have added...

forum.ih8mud.com

Where it is import for CATs, that engine reaches normal operating temp. As running too cool can give a CAT code like you're seeing. But I'd think it would be more likely both CATs (P0420 & P0430). I've actually not seen this cool running set off CAT codes in a 2UZ, only in GM engine. A properly maintained coolant system is one key to a health running engine, and one of the most over looked system. So I'm not saying this is not your issue or a part of it! But I'd look else also.

High temp can be from: stuck thermostat (not fully opening), Low coolant level, Failing fan fluid clutch, Drive belt slippage, Clogged radiator fins, Internal coolant system clogging, Bad radiator cap. It can also be from lean fuel mixture and Clogged CAT.

Low temps can be from: Weak thermostat (opening to easily) or Rich fuel mixture.

I recently saw temp going up fast on HWY climbing mountain passes, in 07 w160K. Temp seemed to climb to high and too fast. Not excessive, but I did notice. I found some (not a lot) clogging in radiator fins from bugs, etc., non OEM gas cap (new), heavy positive battery cable white acid build-up, reducing current flow damaging battery, fuel pump not working as designed (not tested, just replace and corrected stall issue), clogged CAT P0420 (replaced it). In a seemly well (Lexus dealership) maintained VVt w/160K .

 

[BullElk]

Where did you see these two different temperatures of 195F & 185F?

I may not have actually seen two different Tstats. I may just be thinking about the consistent idle temps of my '99 and 2000 models being 185 and the 2006 being 195 degrees. I just figured it was Tstat related.

...Failing fan fluid clutch...

Would this be evident as a problem only when idling? My issue now is only when 75 mph and 2800+ rpm.