My husband and I just bought a second car for him to drive to and from work in from an auction. It seems to run well and doesn't overheat, but the radiator water feels a bit oily. It's clear and water soluble - the oiliness washes away with regular tap water. Would that be coolant?

We have a mechanic coming to look at it on Wednesday, but I'm worried it could be the head gasket. There's no frothy residue anywhere and the oil is nice and dark.

What does it taste like?

Quote:

There's no frothy residue anywhere and the oil is nice and dark.

The oil should be a nice golden colour. Dark oil indicates it needs a change.

If it was a blown headgasket you'd have creamy brown oil and frothy oily gunk floating around under your radiator cap.

I'd be suspecting coolant that's gone way beyond it's use by date and when combined with the dark oil, a car that's skipped a service interval or four.

Life_goes_on wrote on Jan 23^rd, 2012 at 8:00pm:

Quote: There's no frothy residue anywhere and the oil is nice and dark. The oil should be a nice golden colour. Dark oil indicates it needs a change. If it was a blown headgasket you'd have creamy brown oil and frothy oily gunk floating around under your radiator cap. I'd be suspecting coolant that's gone way beyond it's use by date and when combined with the dark oil, a car that's skipped a service interval or four.

Thanks, Life. There's no gunk and the water appears to be clear. I hope it's coolant - I guess we'll find out Wednesday!


FD, I didn't taste it.

When you buy a second hand vehicle it's always best to assume that its never been serviced (even with full service history) and get a major service done on it - all oils, filter, plugs, air filter, grease, radiator fluid change, brake check/fluid change etc.

The mechanic that's coming on Wednesday is doing a RWC and giving it a quick look over - if it passes, I'll take it into the shop for a major service.

Thanks again :)

You're welcome. Let us know how the look over goes.

freediver wrote on Jan 23^rd, 2012 at 7:52pm:

What does it taste like?

That reminds me of a First Aid course I went to. The instructor was talking about cerebro-spinal fluid coming from the ears in the case of skull fracture. A voice piped up, "What does it taste like?" We then had a collective grossed-out moment.

Coolant is typically greenish in colour and feels slimy to the touch. It's mainly ethylene glycol, and it can give you a severe stomache ache even by tasting it. A few years ago, there was a case where Spanish bulk wine was contaminated with ethylene glycol. Several people ended up in hospital.

Annie Anthrax wrote on Jan 23^rd, 2012 at 7:45pm:

My husband and I just bought a second car for him to drive to and from work in from an auction. It seems to run well and doesn't overheat, but the radiator water feels a bit oily. It's clear and water soluble - the oiliness washes away with regular tap water. Would that be coolant? We have a mechanic coming to look at it on Wednesday, but I'm worried it could be the head gasket. There's no frothy residue anywhere and the oil is nice and dark.

Sorry a bit late: of concern is that you seem to be saying that there is water in the coolant reservoir and not coolant.

That would explain what you are saying as there would still be traces of coolant in there as well. the problem is the water - only coolant goes into this reservoir. Water will cause damage eventually.

Dnarever wrote on Jan 25^th, 2012 at 8:23am:

Annie Anthrax wrote on Jan 23rd, 2012 at 7:45pm: My husband and I just bought a second car for him to drive to and from work in from an auction. It seems to run well and doesn't overheat, but the radiator water feels a bit oily. It's clear and water soluble - the oiliness washes away with regular tap water. Would that be coolant? We have a mechanic coming to look at it on Wednesday, but I'm worried it could be the head gasket. There's no frothy residue anywhere and the oil is nice and dark. Sorry a bit late: of concern is that you seem to be saying that there is water in the coolant reservoir and not coolant. That would explain what you are saying as there would still be traces of coolant in there as well. the problem is the water - only coolant goes into this reservoir. Water will cause damage eventually.

No, no, no. The reservoir is just an overflow from the radiator. The cooling system can be run using either a mix of water and coolant (basically a corrosion inhibiter) or just water (ideally distilled water to inhibit shale and corrosion).

While you are meant to add coolant to the reservoir, it's still shared with the radiator itself and will contain a mix of water and coolant. The cooling system runs under pressure so as to raise the boiling point of the coolant (radiator caps have different pressure ratings - a faulty radiator cap can cause overheating) with the reservoir being attached to, but outside the pressurised system (flow to it regulated by the radiator cap - think of the radiator cap as a switch or flow regulator).

As an engine goes through its heat cycles coolant is moved between the radiator and the reservoir (governed by the radiator cap). Engine heats up - reservoir level rises. Engine cools down - reservoir level decreases. The fluid level in the reservoir should always be at a minimum level to stop air getting into the cooling system.

Thanks DNA. The mechanic has cancelled because we have some minor flooding in the area, so it'll probably be next week til we know.

When coolant exceeds its service life it begins to break down and will result in a slimey sludge floating on top of both the radiator header and the reservoir.

This is very noticable on higher mileage vehicles who have had a lot of water put into the system at one time (radiator repair/replacement) without a full system flush being performed.