"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.