Need some help lads.

I have an 07 RRS SC with ~88K miles. I went to the garage this morning and discovered a small puddle of fresh coolant on the floor. I put the Sport on some jacks, crawled underneath, removed all the under carriage protection and used a light to see where the leak was coming from. The only place where I can see coolant is the soaked piece of foam that the radiator rests on. It's only wet on the driver's side. It's not leaking from any of the hoses (they all look dry underneath), or from the thermostat housing. The overflow tank is dry as well. I can only assume it's either the radiator or the intercooler because I can't seem to find where the coolant is coming from. The strange thing is (or maybe not) that it doesn't leak while it's running. For giggles, I started it, let it warm-up to operating temperature, and then let it run for about 20 minutes. No leaks, no smell of burning coolant... When I turned it off, it started leaking after about 15 minutes.

Not sure if it's related, but I've been getting an intermittent Low Coolant warning for the past couple of weeks. It's not low at all, never has been. I assumed it's a sensor going bad, because I only get the warning under hard acceleration.

Any ideas? Any tests I can perform, other places to look before I shell out the big $$ to a dealer?

Thanks in advance for the help! '12 RRS SC
'07 RRS SC
'11 Honda Odyssey Touring Elite (sigh...)
Gone, but not forgotten
'02 RR
'05 LR3 SE7 (Best off-road rig I've ever had) let her go @ 100K miles

Hi, it won't be the intercooler as this is just for cooling the air going into the engine and should only contain air (although there is usually a little oil from the crankcase breather too).

Most likely the radiator matrix has rotted from the outside and has perforated; tends to occur in the corners where there is a build up of leaf debris, road salt and general crap. Can rot from the inside if your coolant is very old or weak and has lost its anticorrosion properties.

You could try pressure testing it yourself if you borrow a pressure testing tool or buy one but that will only really confirm what you already know?

Replacing the radiator is likely the best option. 2008 MY Java Black TDV8 HSE

Paddi, the S/C intercooler is an air/liquid system not an air/air system like the diesels. The intercoolers sit either side of the supercharger on top of the engine. The intercoolers have a dedicated radiator in front of the engine cooling radiator and there is an electrically driven pump. 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

Thanks gents.

Is it safe to say that if:
1. All the hoses are dry
2. The matrix, or veins of the radiator are wet, or look like they've been wet at one time
3. The over flow bottle is dry underneath

= I need a new radiator?

What about the low coolant warning under hard acceleration? How would a bad overflow cap contribute to any of the problems above.

Should I replace both the large radiator and the one in front, which is the smaller one (I think it's the condenser)? There's one that is smaller still, that sits in front of the condenser, and has a tag PCC 500260. So in total, 3 parts (the big radiator part number PCC 500213, the one in front--can't see the part tag, and the one in front of that, which is PCC 500260) that look like radiators. I think the one in the middle is the is the one leaking. Well, it's the one that has all the coolant on it and it dripping every so often.

The picture shows the driver's side (US) bottom corner (not sure why the picture is turned like that). I can't tell if it's wet because the big radiator is leaking or because the smaller aux one is, and is dripping back.

Thoughts?

 '12 RRS SC
'07 RRS SC
'11 Honda Odyssey Touring Elite (sigh...)
Gone, but not forgotten
'02 RR
'05 LR3 SE7 (Best off-road rig I've ever had) let her go @ 100K miles

Apologies for the mix-up as I hadn't noted your RRS was a S/C.

You could try changing just the expansion tank (overflow bottle) as a complete unit to rule out a leak and/or faulty level sensor. However it does sound from your investigations so far as if you have leak from the radiator or the charge air radiator. Probably the only way to be sure which is removal. The job looks like a possible DIY except for extracting the A/C refrigerant which needs to be done with special equipment. 2008 MY Java Black TDV8 HSE

The intercooler radiator is the smaller, front one, the air con is the middle one and the engine cooling radiator is at the rear. 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

Too right gents. Today I borrowed a pressure tester and discovered that the radiator is indeed holding ~22 psi for over 5 minutes. I can still see coolant dripping from what I think is the charge air cooler radiator. That's the one that sits between the engine (large) radiator, and the intercooler (about half the size of the engine radiator), right?

Not sure how those two things are related, or even how I can see 22 psi hold steady on the pressure test, but see a relatively steady drip from the charge air cooler radiator.

Kinda lost here... '12 RRS SC
'07 RRS SC
'11 Honda Odyssey Touring Elite (sigh...)
Gone, but not forgotten
'02 RR
'05 LR3 SE7 (Best off-road rig I've ever had) let her go @ 100K miles

I believe the smallest rad is the air charge cooler (intercooler) circuit. The medium sized rad is the air con circuit and the largest rad is the engine cooling circuit.

Does the air con work correctly? 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

You might be right.

The AC works fine, but it's only 65 degrees here last few days. I'm at the dealer now and will report back with what I think we all know-- I need a radiator.  '12 RRS SC
'07 RRS SC
'11 Honda Odyssey Touring Elite (sigh...)
Gone, but not forgotten
'02 RR
'05 LR3 SE7 (Best off-road rig I've ever had) let her go @ 100K miles

Ok, so it's the intercooler. Dealer diagnosed this morning. Also needs a new expansion tank and sensor... It's gonna be a pretty hefty bill I have a feeling.  '12 RRS SC
'07 RRS SC
'11 Honda Odyssey Touring Elite (sigh...)
Gone, but not forgotten
'02 RR
'05 LR3 SE7 (Best off-road rig I've ever had) let her go @ 100K miles

!

Hopefully they'll be kind to your wallet... 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

Too right!!

Keep you eyes for a gofundme link posted here soon!!!  '12 RRS SC
'07 RRS SC
'11 Honda Odyssey Touring Elite (sigh...)
Gone, but not forgotten
'02 RR
'05 LR3 SE7 (Best off-road rig I've ever had) let her go @ 100K miles

$954 later and my S/C is back in commission.

It ended up being the intercooler radiator and coolant tank sensor.

Thanks to everyone for the suggestions and help! '12 RRS SC
'07 RRS SC
'11 Honda Odyssey Touring Elite (sigh...)
Gone, but not forgotten
'02 RR
'05 LR3 SE7 (Best off-road rig I've ever had) let her go @ 100K miles