98 s70 T5 Slow coolant leak, not mixing fluids

Post by **cn90** » 09 Sep 2015, 16:49

captainkong wrote:Is there a particular brand you would recommend using for the core and hoses? I want something that will last a long time. Don't want to do this again.

thanks

Did you read the link?

Post by **cn90** » 09 Sep 2015, 16:52

RussB wrote:Perhaps you should diagnose the problem rather than throw time and money at the car?

Under normal circumstances, this statement is true, but knowing these cars and with tons of users' experience in forum, it is the heater core and/or the heater hoses and/or the turbo coolant hoses (which can burst any time).

Post by **RussB** » 09 Sep 2015, 17:43

cn90 wrote:
RussB wrote:Perhaps you should diagnose the problem rather than throw time and money at the car?
Under normal circumstances, this statement is true, but knowing these cars and with tons of users' experience in forum, it is the heater core and/or the heater hoses and/or the turbo coolant hoses (which can burst any time).

And I agree, but still it's good to be SURE where the leak is coming from. I'd be putting some UV dye in the coolant, lifting up the carpet and looking all over for the leak. That's another good reason to buy parts from FCP...they have a great return policy!

captainkong · Post by **captainkong** » 19 Sep 2015, 07:13

Sorry for not getting back to this post sooner, I've been very busy as of late. Cn90- I did read the link, but was not comfortable getting a heater core off ebay. Behr(oem) heater core instead off FCP. Also used the Video guide from, rspi. Whole thing went quite smooth actually and was a lot easier than I thought it was going to be.

RussB- You're absolutely right! I should have went and bought a kit to test that and could have been 100% certain that it was my heater core...but I didn't. Anyways , as I read/heard it's better to do this as a preventative maintenance job on higher mileage cars to avoid problems later down the road. Here in Wisconsin it gets very cold,and I certainly did not want to be working on a heater core in the middle of winter.

Post by **abscate** » 20 Sep 2015, 03:18

Hope that solves the coolant leak. I had a slow one at the thermostat on the T5 that I just lived with until I did the PCV and could really get to the thermostat and ECT sensor well.

A coolant leak that takes a month to move the reservoir from max to min is one you can live with for a long time. I just pop the hood on fuel stops and do a quick look, so that's every 350-400 miles. I did carry a gallon of mix in the trunk when the T5 used coolant but took it out after fixing

Cees Klumper · Post by **Cees Klumper** » 20 Sep 2015, 05:57

Have a similar slow leak on my 2003 T6 S80. Upon inspection, it seems very likely that the coolant reservoir CAP is the culprit, because I can see two hairline cracks in it, as well as dried up small spots on the reservoir which I replaced about a year ago due to a small leak there. Then I read the advice to, if you have to replace the reservoir, go ahead and do the cap too because likely it's going to fail soon as well.

So if on TS' car the new heater core did not remedy the leak, look at the cap, I see you replaced the reservoir but no word on the cap.

Oh and on my 2002 C70 I just ordered a new heater core. No coolant loss there yet, but 235,000 KMs and thirteen years on the original heater core tell me it's waiting to happen!

captainkong · Post by **captainkong** » 23 Sep 2015, 00:32

Just thought I'd get back to everyone... It's been almost two weeks since I did the replacement, and I've had no coolant loss at all. So it appears the heater core was my culprit.

Cees-klumper- I did end up replacing my reservoir cap a few months back with the blue cap. Reason I replaced the reservoir itself was my float was soaked and not rising like it should. This was causing my coolant light to constantly stay on which is dangerous! coolant loss and a soaked float is a very bad combination!

Thanks again for your time everyone.

Post by **cn90** » 15 Jan 2017, 11:07

Some background info
- 1998 S70 GLT with 185K miles
- Brand-new Volvo OEM radiator at 140K miles, no external leak on the ground. ATF fluid is clean without coolant.
- Brand-new Estonia heater core installed 2015, no leak when I last checked it a few months ago.
- Both turbo coolant hoses were replaced with Volvo OEM hoses, zero external leak.
- Checked everywhere and see no residual coolant traces in the engine compartment.

I have an UNEXPLAINED coolant loss of 1 cup every 2K-3K miles, which I "assume" is normal.
I just keep topping it up on and off.

My theory:
1. Either...H2O evaporated at the cap when pressure exceeds certain values (? such as 15 psi or whatever etc.), very much like a pot of hot water evaporating...
2. Or...Head gasket internal leak (head gasket can fail with time/mileage even without an overheated engine), but the last time I sent oil for analysis, there was no glycol in the oil...

So, I need to ask you guys: what is your "normal coolant rate of consumption"?

Post by **FLXC90** » 15 Jan 2017, 16:48

Break out the blok-chek kit. Due to numerous concurrent wallet drains, I've been driving my XC90 with a chronic coolant loss. Of course mine is obvious, you can hear it burping due to head gasket breach. I keep a gallon of distilled water in the car and top-off as necessary. It's ONLY been six months so far. This spring will be head gasket/RMS/trans side seal/turbo hoses. woo-hoo. Then I can actually start in on the 98 T-5. (as usual, POS70 keeps on chugging!)

Post by **mecheng** » 16 Jan 2017, 10:02

cn90 wrote:Some background info
- 1998 S70 GLT with 185K miles
- Brand-new Volvo OEM radiator at 140K miles, no external leak on the ground. ATF fluid is clean without coolant.
- Brand-new Estonia heater core installed 2015, no leak when I last checked it a few months ago.
- Both turbo coolant hoses were replaced with Volvo OEM hoses, zero external leak.
- Checked everywhere and see no residual coolant traces in the engine compartment.

I have an UNEXPLAINED coolant loss of 1 cup every 2K-3K miles, which I "assume" is normal.
I just keep topping it up on and off.

My theory:
1. Either...H2O evaporated at the cap when pressure exceeds certain values (? such as 15 psi or whatever etc.), very much like a pot of hot water evaporating...
2. Or...Head gasket internal leak (head gasket can fail with time/mileage even without an overheated engine), but the last time I sent oil for analysis, there was no glycol in the oil...

So, I need to ask you guys: what is your "normal coolant rate of consumption"?

Check your radiator cap, I think these cars caps slowly leak a bit. I see a few white stains around my cap even though my reservoir is OEM Volvo and only a 1yr old

98 s70 T5 Slow coolant leak, not mixing fluids

Re: 98 s70 T5 Slow coolant leak, not mixing fluids