Coolant smell in engine compartment

[NSX2398]

I've read all the related FAQs on the topic but they don't seem to apply. I have a '91 and after a 15 min drive (long enough to come up to operating temperature) I can smell coolant outside the car on the driver side.

The smell is stronger after opening the hatch but no green liquid anywhere; the side of the coolant bottle is not wet; the levels never drop noticeably; and I'm able to drive for hours on the highway without it getting worse. In fact, I've put probably 2500 miles on the car since I originally noticed it. The temp gauge behaves consistently and never fluctuates. Car never overheats so I presume there's no air in the system.

I've re-seated the cap since there was some dried green residue on coolant bottle 'ledge' .. haven't seen any since but smell persists.
The bottle doesn't seem to have any cracks anywhere and the hoses aren't wet. Is some smell normal?

 

[nsxtasy]

Originally posted by NSX2398:
Is some smell normal?

No.

The most common places for coolant to leak are around the cap of the coolant tank or if the seam splits, but you seem to have ruled those out.

Hope someone else has some ideas for you...

 

[Soichiro]

Get a new cap for the overflow bottle. They're cheap and after 11 years yours may have partially failed. It could be leaking enough vapor to make the smell but not enough to wet the bottle.

 

[NSX2398]

Tks for the comments .. I have a line on an inexpensive OEM replacement for the tank so I may bite the bullet and do both the tank and the cap

 

[sjs]

In older lesser cars, your symptoms would suggest a leaky heater core valve, hose, or the core itself (like a little radiator) up under the dash. I'm not aware of any reports of this even on an older NSX.

 

[sjs]

Originally posted by sjs:
In older lesser cars, your symptoms would suggest a leaky heater core valve, hose, or the core itself (like a little radiator) up under the dash. I'm not aware of any reports of this even on an older NSX.

Ooops! Just noticed I miread "...stronger stronger after opening the hatch..." Scratch that idea, but there are still pleanty of hoses to check. It doesn't take much.


Ugh! made a mess of this one...


[This message has been edited by sjs (edited 26 March 2002).]

 

[Larry Bastanza]

NSX2398,

I think careful visual inspection from UNDER the car is key here. If you can get it on a lift it would be the best. The two large coolant hose UNDER The tank, which you really cannot see well from the top need to be checked. I was under my car recently, checking on other things when I looked up past the front beam and could see clear to the bottom of these two hoses. Well there was a little "green" residue. So it is time to change the hoses, all 4 front and rear. I think we all have heard the stories about these hoses being suspect when the car gets older. Just an FYI, my 1991 just hit 30K miles.

In addition, I am doing a 90K service since the car is now 11 years old. I do have a lot of faith in Honda parts, so I was also really surprised that when I took out my water pump, there was coolant in the weep hole. My original plan was to not do it unless it needed it, but I have read a few posts recently that suggested even low milage cars had suspect water pumps. Anyway I ordered the new pump, and sure enough my car with 30K really needs it. Frankly the timing belt looked better then the pump did!

HTH,
LarryB

 

[NSX2398]

Tks Larry .. for the record, my car's previous owner had the 90K service incl water pump done by none other than MB himself and I'm only about 5K on the other side. I presume if he thought any hoses were marginal, they would have been replaced.

I have run my hands under the hoses you're talking about and they're dry but I agree that getting it on a lift would be optimum. I was hoping that the dried residue on the seam was an indication of either the cap or a crack on the upper half of the tank that (above the coolant level) I can't see, so I think that will be my first action.

 

[sjs]

Originally posted by Larry Bastanza:
NSX2398,
... I do have a lot of faith in Honda parts, so I was also really surprised that when I took out my water pump, there was coolant in the weep hole. HTH,
LarryB

That's what the weep hole is for. The pump is not 100% water tight, and very small amounts of coolant from the hole does not necessarily mean there is a problem.

 

[Larry Bastanza]

sjs,

I agree, I did not actually see anything dripping, but I think you would agree if I am in there, this is a telltale sign to do the pump now;-). Also it felt a little "crunchy" when spinning it by hand. The new one is very smooth.

I figure it this way. The car is 11 years old. Based on the timing belt and pump replacement, I will not have to go in there for a long time! I use the car about 5K miles per year, so it will probably last thoughout my ownership of the car.

Thanks,
LarryB

 

[Standig]

I own an old fashioned gas station that still does repairs. When we have a 'hard to find' problem as discribe we put a 'dye' in the cooling system and than after running for a while which may also be a day or two later we check with an ultra violet light. It never fails to find the problem.
Stan