DIY: 1998 Volvo S70 GLT Heater Core, Heater Hoses Rebuild!

[cn90]

Two (2) months follow-up.

1. The coolant consumption has stopped, the level in the coolant reservoir stays solid at the same mark during the last 2 months. As mentioned before, the I had to add 1-2 cups every 5K or so.
This issue is now solved!

2. The firewall coupler delete mod works great.

Any questions, feel free to ask, we open 24h a day!

[cn90]

Six (6) months and 10K follow-up.
Rock solid, zero issues.

[mecheng]

Nice write up, but don't you guys find it Ironic that the well regarded heater core has such a serious issue. There should be no excuse for the supplier to not get that dimension correct, it is easy to measure on the OEM model and is an easy change in the mold (tool safe - reduce the pin height in the mold).

To go source unique washers and then play with them to fit is such a hassel, especially for a well regarded part. I would e-mail the mfg so they fix the problem. There is a risk that if you don't get the OD correct, the copper will tear into the plastic on the heater core when it expands due to heat.

I will now personally avoid this part and I'm looking to replace my heater core as a 2nd winter with a syrup smell will annoy me. Strangely, I can't see any leaks, and I'm not loosing any coolant so it must be a small leak.

Does anybody have any experience with Spectra heater core. I can get it for $75. The ebay one shipped to Canada is $95 (shipping and the low dollar is a killer), so I don't want to spend this much if I have to fiddle with it. I can get the Behr model for $140 and although they eventually leak, they seem to last a while before they do.

[cn90]

Just a quick Follow-up 2y/24K miles later (the original DIY post is from April 2015):

1. Ebay Estonia Heater Core works great for winter, nice heat (it is HOT), zero leak so far.

2. Heater Hose mode (using generic hoses but re-used the barb fittings as in the original post) also works great.
Zero problems.
Glad I eliminated all the firewall coupler, O-rings convoluted setup.

[dyn blin]

Just a quick Follow-up 2y/24K miles later (the original DIY post is from April 2015):
....

Thanks for posting the long term review- appreciated!

[BEJinFbk]

1. Ebay Estonia Heater Core works great for winter, nice heat (it is HOT), zero leak so far.

+1 - Toasty! Even at -40.

2. Heater Hose mode (using generic hoses but re-used the barb fittings as in the original post) also works great.
Zero problems.
Glad I eliminated all the firewall coupler, O-rings convoluted setup.

Left mine stock - No Troubles.

[ZionXIX]

I replaced my heater core a couple of years ago with the Ebay "Redesigned" core. It has a slow leak and I too am suspicious that it is due to the spacer problem.

[wizechatmgr]

Figured I'd chime in. I also have an ebay core "Swedish Auto parts" with the crimped ends on my '99. I suggest running it through the dish washer on the lower rack first to avoid an oily smell. I used the included o-rings and had zero leakage - at this point it has been in ~2 months in the frozen north east. I did this on a ~30 F day with 2 trash bags and an old washer fluid jug. It was great getting heat with no smell... My opinion is that it may not be quite as warm as the OEM but we'll see how it lasts. I believe the gasket seal (foam) isn't sufficient for the pressure and volume of the air being sent toward it. I may go in and work on fixing this in the summer...

When putting it back together it is critical that you get the metal pipes to mesh just right or you WILL get or have a leak - assuming all else is correct with the tolerances. I wiped mine down carefully and lubed both o-rings and passages on the heater core with antifreeze before insertion. You may need to use light emery cloth if yours was leaking from this interface. You don't need to he-man it tight either, we're just going for tight enough that it isn't loose.

Replacing the heater core hoses after ~20 years in service isn't the worst preventative maintenance idea. Very little cost to replace them now - quite a bit of cost if you crack the head because of a 'preventable' failure. Would suggest replacing the thermostat at the same time. Would boil it first to verify it at least opens. Obviously your finances and your situation will guide you on this suggestion.

The heater core I replaced was built on 11/98 - the sticker was still on it so I'm assuming my build date was close to the end of production or that this is the 2nd core it has had. It had developed pinhole weeping when hot and drove me nuts with the smell. There was no visible collection of antifreeze in the heater box when it was removed.

[ZionXIX]

Does anyone know if the Volvo O-rings work better than the "Swedish car parts" provided O-rings?

[sleddriver]

Great thread! The sled's HHs are original...now 19yrs old. I replaced all of the other coolant hoses with OEM last year. I have a very small leak though I haven't been able to find. At first I thought I had: Where top radiator hose connects to radiator. Just a bit wet. So I tightened it, but still losing coolant since. I've also been adding only water, thus slowly dilluting the coolant, which bugs me. Today I'll go get a gallon of coolant and make up a new 50/50 mix and drain/fill when the engine cools off. I'll also check on 5/8" Gates HH.