Strange gurgling noise

[Nick]

After switching off the ignition I can hear a gurgling noise coming from under the bonnet.  It lasts on and off for a few minutes and then stops and has been doing it for around a week now.

 

All the hoses under the bonnet look OK and there's nothing else wrong, doesn't over heat or drive differently.

 

Any ideas?

[Phil Wall]

Is your air  con switched  on or  off?

[Steve Cargill]

I’ve heard the gurgling noise has been linked to a BHG, but it depends on where it's coming from.

1)Does it use any water from the expansion tank?

2)When it’s doing it open the bonnet and see if you can locate the source.

3)When it’s cold check the level in the expansion tank and also take the radiator cap off and the water should be up to the brim.

4)Does the temperature gauge go up to halfway after a few minutes driving and then never move or will a few minutes WOT make it go very high and then rapidly drop again?

5)Pray it’s not a BHG

[Branners]

when I blew all the water out of my engine at Trax and then filled it back up I found it gurgled a lot until I ran it for a while with the heater full on and then the heater full off.

 

Might also be worth checking the expansion tank and the rad cap to make sure they are okay.

 

JB

[Nick]

Phil,

 

The air con is switched off.  Come to think of it the heater's taking bloody ages to warm up, I'm sure it wasn't as bad last year.

 

Steve&Branners,

 

Thanks for the suggestions, I'll see if I can get to the bottom of it tomorrow.  The car's only done 33K so it'd better not be a BHG!!

 

 

 

[Branners]

I didnt read it properly last time, if its when the ignition is off then do check the expansion tank and also the rad cap, basically my car was bubbling for a couple of weeks before Trax and I didnt do anything about it, turned out the rad cap was totally shagged and so wasnt doing its job and just let all the water come out of the expansion tank.

 

JB

[Rob]

You might have had a cat sleeping in there overnight, and the gurgling is just the blood boiling in its chest cavity after a hard run under high boost.

[Nick]

Rad cap, ok got it.

 

It's going to have to wait until Monday though, I'm off to Ireland this afternoon and I wont have time.

 

I'll definitely look at it before driving the car again.

[Steve Cargill]

Quote: from Nick on 10:46 am on Dec. 20, 2001[br]Rad cap, ok got it.

 

It's going to have to wait until Monday though, I'm off to Ireland this afternoon and I wont have time.

 

I'll definitely look at it before driving the car again.

 

Nick, is that a "The rad cap is goosed and I'm getting another one on Monday" or "I'll check the rad cap on Monday to see if it's goosed"?

 

[Nick]

I've just checked the car and the expansion tank looks empty and there isn't any coolant to be seen when the rad cap is removed.

 

The Rad cap itself looks ok, the rubber isn't perished.

 

What do you reckon, have I a split hose some where or could it be a BHG?  It's only done 35K so I can't see how it can be a BHG!!!

[Phil Wall]

Your gurgling noise is probably  the suction at  the  reservoir tank as there is probably  just  a little fluid in it. This is a normal function but normally the  main system would be topped up by fluid form the reservoir tank.

 

So to identify where the water  is going.

 

 

Check your oil filler cap for white milky   deposits.

 

Check the oils level to see if it has risen.

 

After a run does the  rad  smell of  exhaust gases or oil.

 

If these three are  ok, then a temporary top up  of the cooling  system will be required. Use a mix of between 50% and  70% ethylene –glycol to de-ionised water.

 

Keep an eye on your reservoir tank and check for  a hose or gasket leak get your rad  cap checked, the  rubber  gasket  is not  the  most  important part, its the  pressure release valve that needs  checking.

 

Finally  drain and  refill

 

 

(Edited by Phil Wall at 1:10 am on Dec. 27, 2001)

[Nick]

I've topped it up (3 pints) with a 50% mix of antifreeze and checked for leaks but I can't find any.

 

There's no milky deposits on the oil cap, the oil level is perfect and the rad doesn't smell of oil.

 

It hasn't dropped in the past two days so I'll just keep a close eye on it.

 

Thanks for the advice.

[Chris Wilson]

Are we talking MKIII or MKIV here? If you are in the Midlands or North West i can do a full pressure leakage and gasses in coolant test for you, I am near Chester. MKIV's are not, as yet, prone to cooling problems, although water pumps are now being seen to leak.

[Steve Cargill]

Quote: from Chris Wilson on 8:20 pm on Dec. 29, 2001[br]i can do a full pressure leakage and gasses in coolant test for you,

 

Chris, how reliable have you found these coolant gas testers for BHGs?  Two different places did that test and also pressure tested my system and neither of them detected my BHG.

[Nick]

Chris,

 

MKIV.  It's due for a service soon so I'll ask you to have a look at it then, I'll give you a call next week.

[Chris Wilson]

Quote: from Nick on 7:52 pm on Dec. 30, 2001[br]Chris,

 

MKIV.  It's due for a service soon so I'll ask you to have a look at it then, I'll give you a call next week.

 

Oh, sorry Nick, didn't realise it was YOU! I'll check her out for you. Apologies, never can get my head around web based lists.

 

In reply to another post re how reliable gas in coolant tests are, if the reaction liquid is in date (most places use stuff they have had for 10 years...) it works fine, but of course there has to be gas present AT THE TIME OF SNIFFING, which usually means at idle, the gas may only leak into the coolant under load or boost, so it isn't failsafe. I have a secret method of testing under load though, which has been 100% reliable for me over the years.