Cooling system Q's

[TheIntruder]

1) While changing the oil on a '94 LX, I noticed clear evidence of some dried fluid splatter/residue in the area between the engine and the firewall. The light color suggests that it's coolant, so one of the heater hoses may be breached, and those seem to be the only coolant lines in the vicinity. How common is this, and how much of a pain are they to replace?

2) Even if that's not the issue, I think it's due for a coolant flush anyway. What type of coolant do these engines take? The owner's manual doesn't specify. Even if it can be narrowed down to one of the "Asian" coolants now on the market, there is still the choice between red and blue. The service manual doesn't indicate the need to drain anything other than the radiator, which is simpler than I'm used to so, the job looks pretty straightforward.

TIA

[me109]

I've always used Classic Green antifreeze. I think it's what they came with.

Heater hoses are likely done. There is also a water to oil heat exchanger between the oil filter and block, but I don't think it's all that prone to external leaks.

[1st Gen]

+2 on the heater hoses.

[TheIntruder]

Thanks, guys. I'll take a closer look at the heater hoses, but being able to narrow it down helps a lot.

I guess the BG predates FL22, which is the spec most commonly associated with Mazda.

Coolants have improved since the days of the green IAT type, with a silicate-free HOAT type now the preferred Asian recipe.

Another question -- is there a better version of the parts catalog than that 14-page one floating around the net? It leaves out a lot of stuff, so I can't imagine it as the definitive tome. Or is it?

I've been spoiled by the online catalogs that are the equivalent of what the dealer parts counter uses, but even a PDF would be fine.

[Dixie94Pro]

Thanks, guys. I'll take a closer look at the heater hoses, but being able to narrow it down helps a lot.

I guess the BG predates FL22, which is the spec most commonly associated with Mazda.

Coolants have improved since the days of the green IAT type, with a silicate-free HOAT type now the preferred Asian recipe.

Another question -- is there a better version of the parts catalog than that 14-page one floating around the net? It leaves out a lot of stuff, so I can't imagine it as the definitive tome. Or is it?

I've been spoiled by the online catalogs that are the equivalent of what the dealer parts counter uses, but even a PDF would be fine.

Sending you a pm....

Sent from my Pixel 4 using Tapatalk

[me109]

Oh, there are some small coolant lines running in and out of the intake manifold too. Check those out while you're at it.

[TheIntruder]

I happened by the dealer, so I went in and tried to get some answers.

They determined that the recommended coolant is the Long Life Coolant, which was used before 2005, when FL22 appeared.

Both are green in color, as is regular "green" coolant, but the Mazda coolants are P-OAT chemistry, not traditional IAT chemistry like classic Prestone.

One good thing about the older LL coolant is that it's a concentrate, and not sold as a premix as many are now, so you're not paying for demineralized water that you can easily buy for ~$1/gal yourself at the market, and mix with the concentrate in the proportion desired.

Of course, I have no idea what was put into the car before I acquired it, so all bets are off.

As far the hoses, I was told that one was available, but another wasn't, but they'd need the VIN to be sure which was applicable, which I didn't have on me.

I'll have to dig in and see what I find.

Thanks again.