Coolant Type for GM LQ9 with Mishimoto Aluminum Radiator

[Niferous]

I have a 1984 FJ60 that I recently got a GM 6.0 liter LQ9 swapped into. It has the original FJ60 radiator and an electric fan. When I drive around in 90° plus weather (I live in Houston, TX) the vehicle starts to overheat. I've ordered a Mishimoto radiator to try and keep the vehicle cooler and the fan is brand new and moving a lot of air. My question is with the iron block LQ9 and the aluminum Mishimoto radiator, what type of coolant should I be running?

 

[BurntToast]

What temps did you see with the stock rad?

 

[Niferous]

What temps did you see with the stock rad?

I haven't installed the Mishimoto yet. I just ordered it today. Yesterday it was about 95° while I was driving around and I was getting 240° coolant temps reading it off the OBDII port. I was driving around in stop and go traffic, which doesn't help. I could smell coolant when I finally got to a spot I could turn it off. That was about 60 seconds after I saw the gauge starting to creep up.

 

[HAMBURGLAR11]

I always ran the green stuff without issue. Stay away from dex cool.

 

[cps432]

You’ll need to make sure you properly ground the aluminum radiator. If the coolant becomes charged it will slowly eat holes through the radiator as it begins to plate the inside of the iron block with aluminum.

If I’m not mistaken the Mishimoto rad comes with a ground strap. Defiantly use it. There’s also a radiator cap type ground that has a sacrificial probe that takes the corrosion before it hits the rest of the system.

You can run your standard green stuff with this setup as long as you’re grounded.

 

[Snicklephritz87]

Zero issues with dexcool. From my understanding the dexcool acts as less of a conduit for electricity. A lot of people hate it. But i think that’s from improper flushing and lack of routine maintenance.

I had the grounding issues with my last radiator and it started to leak. I used the greebI use a CBR in my fj40.

 

[Niferous]

Thanks for all of the feedback. I have four gallons of red coolant from O'Reilly as I kept doing research on coolant after posting this. I found the attached info and went out and bought some red coolant. The radiator should be here tomorrow and I had planned on filling it with that.

 

[Spook50]

No affiliation, but I'm a major shill for AMSOIL stuff.

Now that the weather is cooling off, I notice I have heat a LOT faster in the mornings than I previously did with Toyota Red coolant (which I ran with Water Wetter). Clear indication that the AMSOIL is transferring heat far more effectively.

The most critical thing, as was already said here, is to make sure when you get it, that the aluminum radiator is grounded. What I would do is ground both the radiator and the block to a shared spot on the body. This way the aluminum radiator, steel body and iron block are all electrically bonded and will prevent electrolysis and premature failure of the radiator.

 

[dbbowen]

I used green in my last aluminum radiator from FSR and it ate it away from the inside. I’m back to the red Toyota concentrate.

 

[cps432]

I used green in my last aluminum radiator from FSR and it ate it away from the inside. I’m back to the red Toyota concentrate.

Maybe I’ll start using it too with my rebuild.

 

[dbleon]

Green no good with alum radiator in my experience

Been using GO5 for over ten years with good results

 

[dbbowen]

Maybe I’ll start using it too with my rebuild.

So far so good on mine. I’ve been checking the voltage monthly. I should probably check the Ph too

Green no good with alum radiator in my experience

Been using GO5 for over ten years with good results

Haha same here. Green coolant cost me like $800 to replace the ate up first rad. It was within spec for voltage and not in electrolysis range but who knows

 

[cps432]

How do you check the voltage?

 

[Spook50]

How do you check the voltage?

Easy check. Negative probe on the negative battery terminal, and positive probe in the coolant, being careful to not be touching the radiator itself. You want to make sure there's less than 0.4VDC (obviously, the lower the better) between the coolant and the battery's negative terminal.

This tells you the condition of the corrosion inhibiting additives in the coolant. If you want to make sure your radiator is properly bonded electrically between the block, battery and body, you just check for voltage differences among those three point. If no voltage difference, you're good to go.

 

[dbbowen]

Easy check. Negative probe on the negative battery terminal, and positive probe in the coolant, being careful to not be touching the radiator itself. You want to make sure there's less than 0.4VDC (obviously, the lower the better) between the coolant and the battery's negative terminal.

This tells you the condition of the corrosion inhibiting additives in the coolant. If you want to make sure your radiator is properly bonded electrically between the block, battery and body, you just check for voltage differences among those three point. If no voltage difference, you're good to go.

@cps432 yeah he pretty much nailed it haha

 

[cps432]

Easy check. Negative probe on the negative battery terminal, and positive probe in the coolant, being careful to not be touching the radiator itself. You want to make sure there's less than 0.4VDC (obviously, the lower the better) between the coolant and the battery's negative terminal.

This tells you the condition of the corrosion inhibiting additives in the coolant. If you want to make sure your radiator is properly bonded electrically between the block, battery and body, you just check for voltage differences among those three point. If no voltage difference, you're good to go.

Excellent! Thank you, I will be adding this to my regular check list going forward. That’s actually a huge help. Never thought of checking coolant voltages…