Small coolant leak in passenger footwell. Heater core?

[JoeAvaya]

Hi all. Complete novice to any form of mechanics so bare with me. Volvo 740 GLE estate 1987. Lifted the mat up in the passenger footwell and dabbed with a bit of tissue and it’s a reddish colour. Not completely soaked but damp enough. Lifted the carpet and underneath is dry so I’d assume the leak isn’t a bad one. Heater isn’t the best in the vehicle and barely gets warm. Cannot see where the leak is coming from by looking under carpet etc. rear footwells etc are fine. Heater matrix/core knackered? Any ideas on where/who I should contact with regards to diagnosing the problem? Price point if it is the core that needs a full replacement? Am I good to leave it for the time being (I’m currently signed off work so am not using her much at the moment due to injury) I’m based in the East Midlands and don’t fancy taking her directly to Volvo as I’m sure this would cost a small fortune. Any tips/info would be great. Regards, Joe.

[griston64]

Could be the heater control valve which is a fairly common failure point on these cars. It should be green or blue rather than red though

[JoeAvaya]

It’s like a shiny slippery substance on your hands when you feel it. Reddish tint when dabbing a tissue on it. Middle of passenger footwell. Seems dry elsewhere in the footwell aswell. I do have a sunroof which I haven’t opened (I daren’t). Owned her about a year and she’s as solid as rock everywhere. Heating has been a minor issue though. Doesn’t get warm for ages and the direction doesn’t change correctly when settings are changed. I have no idea what I’m doing with regards to doing checks to see where the leak could be coming from. I have read about heater core replacement which seems like a total nightmare and expensive

[RollingThunder]

Originally Posted by griston64

Could be the heater control valve which is a fairly common failure point on these cars. It should be green or blue rather than red though

Unless the PO has used pink/red coolant?

[Moomoo]

You can usually smell it!🤔

[JoeAvaya]

Originally Posted by Moomoo

You can usually smell it!🤔

No smell really. I’ve recently had my car deep cleaned so wondered if the red reddish colour may be down to the cleaning products residue and could be water but the slippery/shiny complexion of the substance says otherwise. It doesn’t seem to be wet from any of the sides and dripping down to the middle so I’m stumped.

[griston64]

Originally Posted by JoeAvaya

No smell really. I’ve recently had my car deep cleaned so wondered if the red reddish colour may be down to the cleaning products residue and could be water but the slippery/shiny complexion of the substance says otherwise. It doesn’t seem to be wet from any of the sides and dripping down to the middle so I’m stumped.

Have you lifted the carpet to get a better look ? How much coolant are you losing from the header tank ?

[JoeAvaya]

Originally Posted by griston64

Have you lifted the carpet to get a better look ? How much coolant are you losing from the header tank ?

Yes lifted the carpet and doesn’t seem wet underneath at all. Literally only spotted yesterday so haven’t checked the coolant levels yet. She’s not been driven since I noticed so will check later on. Will report back my findings on coolant level. It isn’t absolutely soaked and only in a small area. Poor heating upon a little internet research is ringing alarm bells. Non AC model also if that makes any difference.

[griston64]

Originally Posted by JoeAvaya

Yes lifted the carpet and doesn’t seem wet underneath at all. Literally only spotted yesterday so haven’t checked the coolant levels yet. She’s not been driven since I noticed so will check later on. Will report back my findings on coolant level. It isn’t absolutely soaked and only in a small area. Poor heating upon a little internet research is ringing alarm bells. Non AC model also if that makes any difference.

Your poor heating could be caused by a dodgy thermostat. It could also be a stuck heater control valve. How quickly does the car get up to temp and does the needle on the temp gauge sit nicely in the middle ?

[JoeAvaya]

Originally Posted by griston64

Your poor heating could be caused by a dodgy thermostat. It could also be a stuck heater control valve. How quickly does the car get up to temp and does the needle on the temp gauge sit nicely in the middle ?

Car gets up to temp fairly quickly and stays bang on in the middle to be honest. She’s only on 74k so barely run in. Runs like a dream (bar a whining fuel pump I’m going to change soon). Due to It being a small leak (from the damp patch I’ve found) from other bits I’ve read online most likely the heater valve (here’s hoping). If I pull the carpets up under the footwell and get a Torch and have a look should I see the reminisce of some leaking if this is the issue?