OEM vs. Aftermarket Thermostat - Coolant System Maintenance

[94SRUNNER]

Hahaha...you’re right. Just unnecessary paranoia

 

[uHu]

.... Would it be worth the time going through and "unbending" the damaged fins.

According to the FSM you are supposed to straighten any bent fins. It states to clean the radiator regularly, and if you use a power washer and bend any fins, use a screwdriver and straighten them again.

 

[94SRUNNER]

According to the FSM you are supposed to straighten any bent fins. It states to clean the radiator regularly, and if you use a power washer and bend any fins, use a screwdriver and straighten them again.

Thanks for the information. I’ll have to tackle this upon return

 

[94SRUNNER]

A follow up to my cooling system journey...

My last post was updating with some observed high temperatures while on vacation. Thankfully, that was a one-time deal. For the remainder of our vacation and on the return trip from Florida back to Ohio, we experienced ambient temps in the low to mid 90's, with moderate humidity and lots of sun. Highway speeds ranged from 55-70mph. Coolant temps ranged from 186-193*, peaking at 195* pulling long grades. Over all I have been very happy.

This is my wife's DD, so I like to make sure it is running at peak performance. She is learning to pay better attention to the gauges and knows what to look for.

 

[94SRUNNER]

Another update to the cooling system saga...

This past Friday, I decided to install a new OEM fan clutch to test and see if there was a noticeable difference to Aisin unit I purchased from Amazon.

That is when I discovered this...

I called around to my local dealerships and fortunately one of them had the o-rings in stock.

 

[94SRUNNER]

After driving with several heating and cooling cycles the joint is dry.

 

[2001LC]

I've seen that bad practice a few times. Where shop/shade tree mechanic uses FIPG on the O-ring. You can bet they used something other than the 1282B FIPG as well.

Good JOB!

 

[94SRUNNER]

Thanks. They really slopped it in there, fortunately it cleaned up pretty nicely.

I've seen that bad practice a few times. Where shop/shade tree mechanic uses FIPG on the O-ring. You can bet they used something other than the 1282B FIPG as well.

Good JOB!

 

[Biga27110]

Thanks. They really slopped it in there, fortunately it cleaned up pretty nicely.

Did the OEM fan clutch make a difference? Was it hard to install?

 

[04UZJ100]

I think so! I get on my soapbox and beat the drum often in mud on this.

Proper care of coolant system is the most import PM we can do. It is right up their if not more important than lubes and filters. I'm seeing more and more blown engine due to coolant issues in our aging fleet. For the non-heavy duty wrencher, thats a ~$13K repair bill at a Toyota Dealer

I've developed a theory, that running coolant system just 1/2 inch or so low is causing premature heater tee and radiator top plastic failure. That air gap leaves plastic exposed to air, out of the coolant which has a plasticizer to keep plastic health. That the post 03 pink (Toyota SLL) aren't faring as well as systeming using Red (Toyota LL coolant) which are seeming to fairing better. This may be due to coolant itself, or more likely due to longer flush cycle of SLL which I don't advocate.

I use only Toyota products (coolant & parts) in coolant system period. I check coolant very often and recommend everyone do the same. The only exception is radiator.

What’s your interval and recommended service? I’ve flushed mine once and have done 1 drain and fill...pretty much by the book.

Drain/fill ever 2 years? 1 year?

Where are you hearing about 2UZ failures due to coolant issues. Outside of radiator failure or mechanical failure resulting in complete cooling system failure - what fluid related issues do you see?

 

[2001LC]

What’s your interval and recommended service? I’ve flushed mine once and have done 1 drain and fill...pretty much by the book.

Drain/fill ever 2 years? 1 year?

Where are you hearing about 2UZ failures due to coolant issues. Outside of radiator failure or mechanical failure resulting in complete cooling system failure - what fluid related issues do you see?

Not keeping up with lubes reduce life of components, but I've only seen catastrophic failure from coolant low issue.

Keeping an eye on coolant level is of utmost importance. A system running just a little low leaves radiator top and heater tees exposed to air (air pocket), which is not good on plastic.

Full flush (~4 gallon):

98-02 (IIRC) Toyota LL (red), full flush the early of 2 yr or 30K miles is perfect.

03-18 coolant systems that use the Toyota SLL pink. Factory recommendation of a full flush is the earlier of 10 yr or 100K miles, then 5yr/50K thereafter. This 10/100k, 5/50K is to long IMHO. If one does follow factory, then I suggest you do a one gallon drain a fill every year or two after first 3 years to freshen coolant, using Toyota coolant. EVEN BETTER, WOULD BE TO CUT FACTORY RECOMMENDED INTERVAL IN HALF.

In mud we reading about more of these which is very small sample of fleet. I also hear of others from Shops around town. I've had one, The Unicorn, I replaced engine in, due to overheating. It's hot heater tee was blown and melted from exhaust gasses entering coolant system from warped heads. I've clues it was running slightly hot and slightly low on coolant for 20K miles.

The number one issue is low coolant due heater tee failure that go unnoticed. Other areas are radiator top failure, but most notice this leak before damage is catastrophic. Water inlet due to improper installation during time belt job, water pump failure, water bypass joint front or rear, front water bypass hoses and radiator hose at gooseneck.

 

[04UZJ100]

@2001LC As always, thanks for your wealth of knowledge.

 

[94SRUNNER]

Did the OEM fan clutch make a difference? Was it hard to install?

Not enough seat time for me to determine if it has made a difference, as it is my wife’s DD. However I did notice that in +90* ambient temperatures, previously I’d see 197* while sitting at a long red light or stopped traffic. On Monday with the ambient temps in the 90’s,we hit heavy traffic while leaving a Labor Day parade and it only hit 195*.

I’ll follow up once I get some more drive time.

 

[94SRUNNER]

The repaired thermostat housing got its first full day of testing yesterday, with ambient temps in the low to mid 90’s. Happy to say that the o-ring and FIPG seals are holding strong.

However, the coolant by-pass hose that I believe goes to the oil filter has a non-factory worm gear that I found to be about a half turn loose and was slightly seeping coolant

I tightened it up and will monitor for now. Tracking down part numbers to replace it ASAP.

If anyone has the part number for this hose as well as for the clamps, that would be a great help.

 

[2001LC]

Punch in your VIN and verify part & location www.partsouq.com

All three hoses and clamps

 

[94SRUNNER]

Thanks!

Punch in your VIN and verify part & location www.partsouq.com

All three hoses and clamps
View attachment 1782504

 

[2001LC]

Your welcome.

Funny I just did on a 00LX Lexus Dealer maintained. History showed Dealer repaired leak. They used non OEM hoses and screw clamps, I was so surprised. It leaked, but dry as a bone now with all OEM.

 

[94SRUNNER]

It’s a shame that a Lexus dealer would use non-OEM. I’d be surprised if the customer was charged for non-OEM and not the OEM.

 

[94SRUNNER]

Just thought I'd follow up as its been about a year and a half.

Over the last 6 months or so, I've noticed a very slow coolant loss in the reservoir. One known leak location was at the top oil cooler hose. Its been a little pink and crusty for a while but never really got bad. Repaired that with a new OEM hose and 2 new OEM clamps. The other two I discovered today while I was poking around.

The prime culprit seems to have been the upper radiator hose on the engine side.

One of the issues is the fact that I had the wrong clamp on the engine side of the hose. It should have the black clamp (90466-41008).

Its been seeping for some time at the water by-pass fitting...

The aluminum had a lot of scaling, which made it apparent that it has been seeping for a while. I cleaned that up, installed a new OEM hose and clamps. The coolant was topped off and the system burped.

The third area is on the thermostat housing where the o-ring is. There is a evidence of a slight seep at the bottom, with a little pink staining. For now I'll monitor it and it will be address when the timing belt and water pump service is done once the pandemic eases.

 

[94SRUNNER]

Well I've found yet another small coolant leak. This time its at the coolant overflow line where is meets the neck of the radiator. Very small but had noticed a very minor drop in the coolant tank over the last two months. A new one is on its way via PartSouq. The radiator is beginning to brown, so that is getting swapped this fall.