"Brown plastic of death" - pre-emptive radiator replacement?

The last time I had my truck in the shop, my mechanic recommended I just go ahead and replace my original radiator along with the heater control valve. He took me back and showed me how the radiator plastic has turned a dark brown which is very obvious when you compare it to other black plastic parts under the hood. Mine has the "Denso - Michigan" stamp on the top from when they used to be made there. He says that you can get no warning and the top can just split, and it can be catastrophic, at best stranding you somewhere, and at worst causing engine damage. I have the 5VZ-FE which would probably tolerate it pretty well, but I'm more worried about being an hour out on national forest roads and stuck out there without cell service. He recommended doing the heater control valve too since it can fail and you can lose your coolant that way too.

Just wondering if others have done this as a pre-emptive measure?

I found this thread on V8 radiators but not a ton else. This thread mainly deals with Camrys and Avalons but my radiator looks just like the one in OP.

I'm going to do upper and lower radiator hoses too. Was thinking about the thermostat too since all the coolant will be drained any way. Anything else? I'm only 37k miles into this timing belt so too early for that, although it is a Gates belt, not OEM.

2004 Tundra AC 3.4 L V6 manual

 

A lot folks put in another Denso radiator but not the same as before (have seen China or Taiwan instead of MI) although appear to be the same as a new Toyota MVP (value line) replacement. Had good luck with the one in a Tundra but another in a Tacoma only lasted about 2 years so 2nd time used a LAPS with lifetime warranty cause couldn't wait to take a chance again on shipping another of the same....

https://www.tundras.com/threads/swapping-radiator.141348/#post-3756987

 

If you have the money and time do it all at the same time.

my radiator blew up one day because the thermostat had gotten stuck. Waited 3 days for the new denso radiator + upper and lower hose. replaced everything plus 3 gallons off coolant.

I continued to overheat because I didn’t change the thermostat. I couldn’t afford anymore downtime. Had to bite the bullet and pay dealer prices for an oem thermostat and Gasket.

I suggest buying a new Radiator cap also. Buy from rockauto not Amazon

-Denso brand radiator and cap,
-Aisin brand thermostat & thermostat gasket.

 

We're all about maintenance here, and maintenance is preemptive replacement of parts. They're synonymous. The alternative is waiting till they fail. There are very, very, very few parts that anyone on this site is going to recommend "just waiting till they fail" to replace.

Hadn't ever considered the heater control valve, though. Anyone? On my 98 Tacoma with 330,000 miles, it had been slowly weeping for years and hundreds of thousands of miles, but never got worse. Just a little crusty red/white buildup around it.

 

I always recommend replacing with the timing belt. If you search against my name with "125k" you'll see me say the same shit over and over and over again, and from others alike:

Read this, reply #8: https://www.tundras.com/threads/new-toyota-owner.153710/#post-3826072
And this, reply #: https://www.tundras.com/threads/please-help-with-this.153457/page-2#post-3822633

Those two posts pretty much cover it. There's a lot of other preventative maintenance stuff in the community megathread, including "maintenance you must do" in the 2nd reply of that thread, see the "After you buy the truck (or sometimes before):" section. You'll even find this advice there:

• Get to a baseline on critical 1st-Gen-Killer maintenance items that needed to be done:
  • Timing belt/water pump/pulleys/tensioner needs to be done every 9yrs/90k miles.
  • Radiator should be done every 125k-150k miles.
  • OEM lower ball joints should be done every 100k-125k miles *IF* they're OEM parts (aftermarket LBJ shouldn't be used, and should be replaced immediately).

 

I have 2 things to report worse than above. First the 5VZ has a great cooling system - even an oil cooler. But its heads can only take 215 a few times and they Crack - ask me how I know.

Second - another expensive thing that can come on many of these radiators that also serve as transmission warmers/coolers is the lines inside the lower portion can corrode allowing cooling into the transmission lines causing the infamous Pink Milkshake. I avoided this catastrophe by doing what you are considering except I would add the coolant thermo oriented with its Jiggle valve pointing down to 6 oclock or else (what caused a 220 spike for me breaking my heads).

So the 5VZ cannot take high heat (not overheating just higher heat than the normal 194) very well at all so careful there. Heads can be 1400-2800 depending on where you get them. Trans (A340s) are now 3K and up for these.

 

The Denso radiator is around $200, so if you are replacing the coolant anyway, may as well do it.

 

$180 at Summit, likely with free shipping, possibly no tax (not sure if they charge tax for every state, they do here b/c there's a brick&mortar location south of ATL): https://www.summitracing.com/parts/dnp-221-0516
$140 at RockAuto, before 5% discount code (I can supply one), and before shipping & tax: https://www.rockauto.com/en/moreinfo.php?pk=4722378&cc=0&pt=2172&jsn=455

Sometimes free shipping and ease of service/returns makes Summit the better buy. Once you add in shipping (usually around $20-30 on something that size), with tax, the 5% off only puts you a few dollars saved, and I'd rather spend the extra couple bucks knowing I can talk to a customer rep at Summit in about 30 seconds, they make returns and order changes a breeze.

 

Thanks. This is what I was looking for. It does look like it's a point of failure for these trucks, so seems like money well spent. Unfortunately I'll be out of sync with my timing belt since it's good for another 2 years/55k miles. But it would be perfect to sync that up, and the labor would overlap pretty well too.

Thanks for the reminder on the LBJs. Fortunately mine were done at a Toyota dealer about 40k ago. I have the record in my toyota.com account (account I made on the recommendation in the community megathread).

I have a manual so one less thing for me to worry about, but going to just get the job done anyway.

 

I read this thread and I'd like to replace my radiator cap and thermostat also. I ordered the Denso radiator some time ago but no time to put that in (or have a shop do it).

Does a radiator come with a thermostat and cap?

If not, what are the Rockauto or Summit parts numbers?

I looked on Rockauto and couldn't find the cap.

 

I got a new radiator from Summit Racing a year ago.
The cost was about $165 with tax (I'm in CA).
The part # for my 2005 access cab 4x4, was DNP-221-0517.
The radiator does not come with thermostat or radiator cap, I don't believe any of them do.
I would suggest either reusing the spring steel OEM Toyota hose clamps or getting new ones. The screw type hose clamps tend to start leaking over time.
Also, the lines from the transmission started leaking at the fittings a few weeks after the install, so be sure they are nice and tight. Usually I would not use any sealer on these, but I ended up putting a little thread sealer on to stop the leak.

 

Just go OEM on these parts. It's not worth the headache. A leaking radiator cap could be catastrophic.

 

No worries. Swapping the rad is only like a 2 hour job maybe 1 after you get the hang of it!

 

Do you take the fan off when you do it?

 

No. You don’t need to remove the fan. Remove skid plate. Drain. Disconnect and remove the overflow. Remove the fan shroud bolts and slip the shroud over the fan toward the engine. Disconnect coolant lines. Disconnect transmission fluid lines and plug with golf tee to prevent fluid loss. Remove radiator and insert new one. That’s from memory but I think that’s all. I can’t remember if the brackets have to swapped.

 

+1 on this procedure. Golf tees are a nice tip. Have used some other plastic plugs b4.

IIRC swapping the brackets will allow the front apron mountung bolts to line up. Here's the start of a thread on Denso experience with bestgen and taco.

https://www.tundras.com/threads/swapping-radiator.141348/#post-3756987

IIRC modification of the top tank mounting nubs allows the rails to be swapped over. Here's deets on method used for swapping rails on the taco install but recall it applied to the bestgen too.

https://www.tacomaworld.com/threads...t-gen-edition.138573/page-11086#post-29990439

Others might try a faster route and wallow out the apron but not my preferred method.

 

Nice. That doesn't sound too bad. I thought you needed to remove the fan but hadn't looked into it.

I don't have any micro cracks in mine. I'm now leaning towards just splitting the difference with my timing belt and doing them all next winter. Then it'll just be my valve cover gasket leak I have left to deal with.

 

How many miles do you have? IIRC my OE ran about 200k on bestgen before needing replaced and about 150k on taco and leaks at tank seams were visible as others mentioned with the red/pink crust. So @shifty` is about right on mileage IMHO.

Have you tried just snugging the VC bolts (without overtorquing) until can swap the gaskets? Have found doesn't usually fix the issue but can slow the leak and smell and mess....

 

I'm a little shy of 230k. My mechanic inspected it which is how I came to learn about this issue to begin with. He told me that it's not an urgency but something that should be on my radar. First it will develop some microcracks. I don't have any of those. It's very smooth, just brown. Going to just wait a bit and do radiator, timing belt, water pump etc all together so it's on the same schedule. Will save some labor and also a few gallons of coolant.

 

The big issue is when the sealant they use on the transmission line pass-thru at the bottom of the radiator give out. Then you start mixing ATF and coolant. Sadly, there's no warning for that, your transmission starts shifting funny if you're lucky, then the transmission dies full of pink milkshake.

We've had at least one guy from Hawaii who had luck flushing his transmission afterward, and it actually worked, but I also think he caught it early. I can't remember who it was that posted the internals and the sealant they used. Maybe @bunke, I think. It was very crumbly, like grout or seam sealer.

 

look at this price difference:

https://www.summitracing.com/search...ordMatch&SortOrder=Ascending&keyword=221-0518

https://www.rockauto.com/en/moreinfo.php?pk=4722942&cc=0&pt=2172&jsn=458&_nck=Ekt6BqBF1pwlXdx0gYlm1esw98pF26vehMm/GG3C/l2QOXSJubi7WSmJDED/poBfgGB2ZttQ+73lW7wn5W7ZTZcFbFYmsuqoXusbzrV7tDjrkxqcJWd0mr3QJE8YaH/vQvn+ETcB+dnZD3N7iSI3iQnD3bvei8jF7mXsRoSNT2silWQvEVHwH0SoAX7JkwUh/D5w4tldUwwj2JXNpdL1HQDT9wnzP6c2U90C8IomBxER98LAK56fqShPdteCBLXRJMelPS99m5LTkyPslB0APqwbjJPbzRA8OKU7lBvSeit1reUp74NGHVju57wpEGZMLGEcYq2MtOll550VApaFePSF4jZi9JT1&_nck=Ekt6BqBF1pwlXdx0gYlm1esw98pF26vehMm/GG3C/l2QOXSJubi7WSmJDED/poBfgGB2ZttQ+73lW7wn5W7ZTZcFbFYmsuqoXusbzrV7tDjrkxqcJWd0mr3QJE8YaH/vQvn+ETcB+dnZD3N7iSI3iQnD3bvei8jF7mXsRoSNT2silWQvEVHwH0SoAX7JkwUh/D5w4tldUwwj2JXNpdL1HQDT9wnzP6c2U90C8IomBxER98LAK56fqShPdteCBLXRJMelPS99m5LTkyPslB0APqwbjJPbzRA8OKU7lBvSeit1reUp74NGHVju57wpEGZMLGEcYq2MtOll550VApaFePSF4jZi9JT1

also do you guys recommend replaces with hoses/cap from rock auto?

 

It happens sometimes ... prices fluctuate. At the time of my posting, the Summit unit was $180 with free 2-day shipping and tax, which would've put it around $195. RockAuto, after tax and paying shipping, would've been around $178. I could've picked up the Summit unit, in person, same day.

You should see NAPA's pricing. They want $331.

 

To hopefully add to the radiator knowledge base, my original radiator lasted 270k miles. Took it to the dealer to get a replacement a few years back, and unbeknownst to me, they installed an aftermarket radiator from Autozone. Wasn't too long before I noticed coolant leaking around the cap. Replaced cap, and issue persisted. Then recently started to notice other coolant leaks. Took it back to the dealer who told me they don't know why an aftermarket radiator was installed (you tell me), but there was a lifetime warranty on the radiator. Great, but I want an OEM radiator. Initial feedback was that new OEM radiator installed would run about $700 - after the credit for aftermarket radiator. Haven't done anything at this point mostly as I'm pissed about the fact that they essentially want me to pay full price to resolve an issue caused by their bonehead decision to install an aftermarket radiator. Anyway, hope someone will get something out of this if nothing other than another example of why it's important to stick with OEM parts.

 

How much did they charge you for said radiator? And does the bill show an OEM part#?

Chances are, the service manager and/or whoever the staffer is responsible for lining up parts for jobs failed to order the part in advance, so they ran to the LAPS and grabbed whatever the LAPS had in stock.

But if they charged you OEM pricing, and listed an OEM part on the invoice, then that's f'ed up, and you may at least be able to negotiate, "Look ... you charged me OEM prices to install aftermarket parts, the least you can do is replace the aftermarket part, and comp the labor for overcharging for what we both know, and this part is showing us, is a far inferior part..."

 

I do not think that they initially charged me for OEM and installed aftermarket radiator, but I haven't run down the paper trail. Too pissed to deal with it at this point. Not that I go to this particular dealer often, but I did notice their invoice last time had two line items - labor and material. That's it. No part numbers, # of hours, shop rate, etc.

Regardless, in my recent discussion with the service manager on the radiator, he has commented multiple times that he's "not sure why an aftermarket radiator was installed." I know and he knows that was a stupid decision. And I had nothing to do with the decision. I told him I have a '21 Tundra in part for this very reason - there was no big rush on getting my '05 back on the road. And that's the angle I'll probably take to say comp at least some of the labor. Overall, my take is that this smaller town dealer has the attitude of "where else are you going to go." Well, I do have options as I often visit a bigger town with a reputable dealer. Not quite as convenient overall, but I can make it work. And need to make it work.

 

yeah that's what i figured. i saw the napa price and was shocked. do you guys also recommend the dayco hoses on rockauto or should i get those from a toyota dealer? just upper and lower, correct? anything else I should replace? thermostat was replaced about 30k ago?

 

It's also worth noting, Summit Racing does pricematch on the to-your-door price, so they will absolutely honor whatever pricing (tax+ship) RockAuto is offering.

On hoses, I have very little input. When it comes to rubber products there are very few brands I trust. Anything made by Continental is one of them. I'd probably go OEM, just because mine have lasted so damn long.

​

 

I stopped going to Toyota dealer years ago. Accumulation of reasons including price and trustworthiness. Example: In 2010 was advised I needed to replace the alternator. Fast forward to 2025... original alternator still working just fine.

Original radiator was replaced at 254k miles with a non-OEM Murray, along with timing belt, water pump, serpentine... 4yrs and 40,000 miles... all is well. Probably be the last time for all that.

 

Went to the Toyota dealership and they ran my truck information and this is the radiator cap they said I needed. But it looks completely different from my old one. It was a little bit hard to put on at first but it went on snug and I could take it on and off properly now. Just making sure this is the right one. Double cab 06 v8



Also notice there is no clip on the hose right in front of the radiator cap. In some of your pictures there's a clip there. Some of the coolant looks to be coming out of that area so maybe it's not actually the cap where I saw a little bit of coolant splatter, but rather coming out of that area with the hose without a clip.

 

Your orginal cap was definitely damaged. The bottom/nipple of your old one broke off into the radiator