stock radiator rust check

[YoJimbo]

Heya everyone, flushing the cooling system of my 85 720.

 

First time flushing this truck for me so I figured I should pull the radiator out to have a look at how it is doing. Rust has begun to eat through a few rows of the fins in the front of the rad.

 

Is this rust significant enough to be concerned? Considering this truck has lived in the tropics for 30 some years it doesn't strike me as much rust....but like Neil said, rust never sleeps... Maybe it's time to start tracking down a better one.

 

 

Just thinking out loud here and looking for a little input from the ratsun crew.

[thisismatt]

That radiator is copper & brass, so it doesn't rust.  It would be green/white if corroding...  Not sure what part you're referring to.

[YoJimbo]

Copper and brass, that makes sense!

 

Still looks like rust to me though... maybe there is something else coming into play. The rot seems to follow the general pattern of the metal cross piece that the rad bolts to. Kind of a squahed flying v shape hehehhe

 

Here is a closer look..

 

 

And alittle closer...

 

host image

Edited July 29, 2018 by YoJimbo

[datzenmike]

The greenish/blue is copper sulfate. It's similar to rust but not oxidation. It's corrosion. It may be like aluminum and once formed it protects the copper underneath or it may be like iron the just rusts away. Either way I would spray paint it a flat black. Why flat black? Because it radiates heat much better than gloss.

[thisismatt]

The reddish looks like bare copper...not sure what's going on

[DrvnDrvr]

30+ years of salty air. What's it look like on the inside?

 

Recoring is probably not a price wise option. Available on EBAY and Amazon @<> $100, but be careful to get one for a 720 and not a D21. Many parts are listed as fitting both and they don't.

 

https://www.rockauto.com/en/catalog/nissan,1986,720+pickup,2.4l+l4,1210385,cooling+system,radiator,2172

 

Edited July 29, 2018 by DrvnDrvr

[YoJimbo]

Thanks for the tip on the paint and the chemistry lesson datzenmike. The corroded zones flake off and disintegrate quite easily under the fingers. Good reminder that copper and brass do break down eventually.

 

Thisismatt, I was thinking the same thing, maybe the copper is starting to show through the black paint. Whatever the case is, the majority of the fins still seem to be solid.

 

Drvndrvr, the innards have a layer of light orange built up across most parts. I'll get a pic of it soon. Sister just showed up and she is hangry, so I better start cooking the dumplings she brought!

 

Definitely going to scrounge up some flat black paint and maybe start tracking down a new rad.

 

Thanks for all the input guys

[YoJimbo]

Here's a peek inside...

 

 

Looks like someone has been adding msg and turmeric to the coolant for awhile! Secret engine preservation techniques?? XD

[datzenmike]

Judging from the rad rot keeping the maintenance up wasn't a high priority so probably rust from the block from not running a quality antifreeze/coolant and changing it every 3 years.... even in the tropics. Always use distilled water to top it up to prevent hard water scale from building up like in a tea kettle.

 

By the third owner the truck is bought cheap and no one wants to spend any money on it and it gets neglected. Transmission and differential oil is good for about 30K miles and should be changed. If you haven't changed it do you know when it was last changed? Maybe the second owner did 80K ago?

 

Has anyone mentioned re-torquing the head bolts to prevent the head gasket blowing out prematurely?

[thisismatt]

Internal discoloration probably is rust from the block. Radiator fins let ok like they were hit by something corrosive...

[DrvnDrvr]

Like datsunmike said, neglect. Wise to flush your cooling system now. If an engine overheats that has dissimilar head and engine metals, aluminum head and steel block, the head gasket will most likely develop a leak and then your really boned.

 

Might want to replace the thermostat while you have the coolant drained. Buy a quality one you won't regret it.

[YoJimbo]

The coolant that drained out was mostly water with a light mix of old green antifreeze. There was not as much swamp skuz living in there as I imagined there would be after all these years. Here's a look at the majority of the grit, grime and scale...

 

 

Flushed as best as I could with garden hose, sprayed back and forth through all the radiator fittings, upper and lower hoses, block drain plug and heater hoses. Sometime along the road someone bypassed the cab heater by connecting the heater hoses to each other via an elbow fitting. Did my best to remedy the bends and flop by re-using the healthy and best fitting length of original hose to make the route a bit more direct and less bent. New hose for all the cooling system is now near the top of the project list (better get some new hose clamps too). It's a bit of a tight bend coming out of the block, hope I can improve it somehow soon. Did not hook the hoses back up to the heater yet because I was short on time and did not want to find coolant swamping into the cab tomorrow morning before work.

 

This is a view of my attempt to smooth out the jalopy heater bypass..

 

Although I did not open the housing to have a look, I'm almost certain there is no thermostat. Seems like a prime fit to compliment the island style heater bypass. Sure enough when the truck is running the coolant is immediate flowing through the radiator....

[YoJimbo]

4 hours ago, datzenmike said:

Judging from the rad rot keeping the maintenance up wasn't a high priority so probably rust from the block from not running a quality antifreeze/coolant and changing it every 3 years.... even in the tropics. Always use distilled water to top it up to prevent hard water scale from building up like in a tea kettle.

 

By the third owner the truck is bought cheap and no one wants to spend any money on it and it gets neglected. Transmission and differential oil is good for about 30K miles and should be changed. If you haven't changed it do you know when it was last changed? Maybe the second owner did 80K ago?

 

Has anyone mentioned re-torquing the head bolts to prevent the head gasket blowing out prematurely?

 

Changed differential oil with gl-5 a couple weeks ago. Found a few curly shavings of metal in it...

 

Planning to change the transmission fluid asap, need to buy a few more liters of that gl-4 sauce.

 

Re-torqued the head bolts a month ago after reading a post where you mentioned it datzenmike. Much more relaxing cruising around town after re-torquing those. Although I don't trust my harbor freight torque wrench a whole lot... Thank you for the heads up on that.

 

[YoJimbo]

4 hours ago, DrvnDrvr said:

Like datsunmike said, neglect. Wise to flush your cooling system now. If an engine overheats that has dissimilar head and engine metals, aluminum head and steel block, the head gasket will most likely develop a leak and then your really boned.

 

Might want to replace the thermostat while you have the coolant drained. Buy a quality one you won't regret it.

 

Definitely glad I finally got the chance to flush out the system a bit. Doing my best to keep this great truck on the road for many more years.

 

Dunno if it was the rain falling on the canopy and the brews I had, but I swear the engine seems like it is running smoother after the flush. If it's only placebo, i'll just call it peace of mind.

[MaxChlan]

If you're in the market for another radiator, I replaced mine about a year ago and was glad I did. I had similar scale/discoloration issues in mine and it gave me some peace of mind. I can look at the part number later today.

[datzenmike]

 

This is a no no. If by passing the heater, seal both ends of the hoses. In effect what you are doing is pumping hot engine coolant directly back to the inlet of the water pump. None of it is going through the rad to be cooled. When not using the heater the heater valve is shut. By passing the rad puts a big load on the cooling system in the summer. Clamp the by pass closed or cut and put large bolts in the ends with hose clamps.

 

ALWAYS run a thermostat. Engine is designed to run around 185-195F for best performance and economy. Maybe the bypass is causing over heating problems.

[YoJimbo]

3 hours ago, datzenmike said:

 

This is a no no. If by passing the heater, seal both ends of the hoses. In effect what you are doing is pumping hot engine coolant directly back to the inlet of the water pump. None of it is going through the rad to be cooled. When not using the heater the heater valve is shut. By passing the rad puts a big load on the cooling system in the summer. Clamp the by pass closed or cut and put large bolts in the ends with hose clamps.

 

ALWAYS run a thermostat. Engine is designed to run around 185-195F for best performance and economy. Maybe the bypass is causing over heating problems.

 

Thanks very much for this info datzenmike!

That bypass has been making me feel uneasy since I found it. Reminds me of the many no budget scrambled spaghetti plumbing scenarios that I've found working on the fish farm. Another reminder to not re-plumb unless you know the whole story. Very helpful to get a straightforward and sensible answer about it. Definitely going to fix it up asap, hoping i get a chance to snag the parts if i finish work before the supply store closes today.

 

Maxchlan, if you can find that parts number I would appreciate it. I'm definitely on the hunt for a solid radiator that will bolt in without too much hassle.

 

Thanks for all the input everyone.

Edited July 29, 2018 by YoJimbo

[Charlie69]

Take your Radiator to a radiator shop and have it cleaned, rodded, and repaired.  If the core is non repairable the radiator shop will be able to tell you.  They can also sell you a replacement radiator solving all your problems

[YoJimbo]

8 hours ago, Charlie69 said:

Take your Radiator to a radiator shop and have it cleaned, rodded, and repaired.  If the core is non repairable the radiator shop will be able to tell you.  They can also sell you a replacement radiator solving all your problems

 

Got a lead on what sounds like one of the last guys in town that repairs radiators, Jimmy the radiator man. Heard a lot of good stuff about him. Planning to take in the radiator day after tomorrow for him to have a look. Motivated to support local crew doing honest business. Hopefully they can spruce up that crusty rad of mine. Thanks Charlie.

 

Dug deep in the scrap bolt bucket at home and work, found a good size bolt for the heater bypass plugs. Cut it in half and got to plugging the bypass. Not very amped about the cheap hose clamps but it's all i could come up with today. Here's to using what's on hand! ?

 

[bottomwatcher]

I live on an island with the salt air environment and radiator fins, home ac fins and pretty much anything non stainless disappears like a bar of soap. That being said I have revived my current radiator a couple of times by removing it and filling it while laying horizontally with muriatic acid. Put the cap on, fill it and let it soak half an hour and it looks like brand new inside. Nice  shiny metal it has worked for me. That acid is some nasty shit but cheap and effective. Good luck!

[datzenmike]

Let mine soak for 3 days with CLR which may be the same thing. Scale just fizzes away.

[Charlie69]

Jimmy the radiator guy might be able to fix your heater core if that is the problem.  I had the heater shut off valve on my 86 720 King Cab start leaking.  I purchased the last one in the Phoenix area according to the parts man.  You can by pass the heater shut off valve with  copper tubing.  The get a 1/2" full flow ball valve not a gate valve and install it inline with the heater coming off the lower radiator hose.  Then you shut the valve off in the spring and turn it on in the fall.

[YoJimbo]

Thanks for the quick replies guys.

 

After giving it some thought, I'm motivated to clean the radiator myself. The fin rot doesn't seem too extensive yet, so i'm planning on hitting it with some matte black like you said datzenmike.

 

Bottomwatcher, any idea what the concentration of that acid you used was?

And datzenmike, is CLR short for chlorine?

 

At work we regularly clean tanks covered in oyster seed with muriatic acid. 4 to 8L of ~30% muriatic in about 4,000L of freshwater will eat through and soften up oysters that are set to the tank, oysters that are anywhere from 2mm to ~15mm in size will almost melt after 2 or 3 days of soaking, sometimes 4. Having a submersible pump running in the tank keeps the water moving and gets the gunk cleaned more thoroughly. This equals less scrubbing and pains in the neck for us...

 

So here's what I'm getting at. If the radiator is grimed up with scale, the block must be also. So if I only clean the radiator I'm missing a significant part of the action. Has anyone had any luck running cleaning solutions through the block and the radiator? I'm contemplating mixing up a medium strength acid solution and running it through the engine for a minute or two to see what happens... But i'm hesitant because i sure as hell don't know what exactly i'm doing!

 

One of the uncles at the parts store talked me out of buying chemical coolant flush one day. He said a lot of guys won't use a chemical cleaner on older vehicles for fear of dislodging large chunks of scuzz which may in turn cause bigger problems than if the chunks were left unbothered clinging to the walls... But if I'm thorough in my work maybe I can get all the chunks out....

 

Shit, late for work. Time for me to go get covered in algae.

 

Thanks fellas it's been fun!

[YoJimbo]

After doing a little more research, using dishwasher soap mixed with distilled water seems to be a method preferred by a few guys that have had success cleaning their cooling systems.

Here's a link to the post https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&amp;Number=2618740

 

Sending an acid through the system seems a bit sketchy to me considering it's ability to mess up metals. But maybe the proper dilution would make it very effective and not harmful to the radiator or block.

Anyone know what types of metals make up a stock z24 engine and cooling system? Earlier in this discussion I learned that the stock radiator itself is copper/brass.

[YoJimbo]

Forgot to mention that i also did a little chemical coolant flush ingredient research at the local auto parts store and Napa yesterday after work while on the hunt for gl-4 gear oil.

 

Could only find one product that listed any ingredients and all it said was "caution: contains alkaline derivatives". If that's the case then it would support the idea of using dish soap.