Chr1s7ian

Hey all, new owner here! So I bought a GX from Arizona last week and road tripped back to the midwest. Closer to the end of the trip, I checked everything at a gas station and realized the coolant overflow tank was low. I added some and made sure I watched the temp gauge like a hawk until we got home. I ordered the parts including a new radiator but I was reading in older threads about something with the transmission being cooked due to a coolant loss? Can someone explain this is lay mans terms? Again I was watching the temp sensor like crazy and the transmission was still operating correctly, should I still be concerned? Obviously not going to drive until I replace the parts but had no clue this was a somewhat common issue... Thanks!

coachstu

I had a similar issue when I first got my 2003 GX470. Got home and overflow tank was low. I filled it up and it dropped again the next day. Filled it up the third day and it's been level ever since. I suspect in my case the seller had a did a drain and re-fill just before I bought it because I haven't had an issue since and I drained it last month and it did the same thing. Took a few days to level out as the coolant worked its way through the system. Run your car at idle for about 10 minutes with the heat full blast, front and rear, then top back off. Also, make sure you've actually got a full radiator and change radiator cap. I doubt you're having a transmission issue.

chiph9

There is a transmission coolant loop in the radiator. I've never heard of a GX radiator failing and allowing the fluids to mix [0], but I supposes it's possible. If this happens, your coolant overflow tank will now hold strawberry milkshake mix..

The dash temp gauge lies to you - it stays in the middle range until there's really a serious problem. If you want to closely monitor the coolant temp, you'll need an ODB port scanner.

Chip H.

[0] Very common on Honda V6 products - Pilot, MDX, Ridgeline, etc.

coachstu

I'm not sure why OP is worried about transmission specifically. Coolant loss should cause a concern, but there are many reasons for that. Primarily, a pin hole leak in the notoriously faulty GX radiators. I didn't read anything in his post that would cause me to believe the transmission is involved, so it seems strange he would worry about that. At this point, I don't see why he's even swapping out the radiator. He didn't indicate a radiator leak was confirmed. Maybe I missed something in the post.

Chr1s7ian

Whoops, just realized I didnt explain the reason why I'm replacing the radiator. So when I noticed the low overflow tank, I checked everything else and seen that the upper radiator hose was leaking the coolant and could see the coolant in that area as evidence but stupidly, when I was messing with the upper radiator hose, I accidentally snapped the overflow hose at the radiators plastic bit. There is no more off that plastic bit being exposed for the overflow line to fit back on. Unless find something that would work at Ace Hardware, honestly I'd prefer the safety of just getting a new radiator for peace of mind. The coolant wasn't mixed with oil (to my understanding) but thats why I was so confused when I seen other posts talking about how the radiator cools the transmission as well.

Also I understand the temp gauge is not accurate AT ALL, but I was just including that to at-least say that it didn't actually "overheat" I guess.

coachstu

Well, maybe it's good you're replacing radiator because that is a common issue on these vehicles. That and air suspension replacement are pretty much a given at 150,000+ miles. It is not a common issue for the transmissions to go out for the reason you're worried about. It may happen, but it's far from common. Don't sweat the trans and get that radiator replaced. Get a new rad cap while you're at it.