V70XC '98 Cooling fan relay

KenC · Post by **KenC** » 07 May 2009, 23:12

Vegas,

Thanks for the diagrams - I'm still waiting for my copy of VADIS to come from ebay Europe.

I didn't have time to check anything tonight...I did price out the ECT sensor & t-stat today - dealer was double on line prices...but it is local (meaning I could get this done Sat). Gonna' check the other two local dealers to see if they are any cheaper...(the dealer I checked sells Porsche, BMW, Benz & Volvo - and is in the high rent area of Seattle; Bellevue

).

Will check to see if the A/C clutch is engaging...what difference would that make?

Post by **Matty Moo** » 08 May 2009, 01:45

If the AC clutch doesn't engage, the compressor doesn't turn, thus no AC. It happens and can be fixed. Mine happens to work fine.

When the AC is engaged, the cooling fan on the radiator is supposed to engage. That's because the condenser puts out quite a bit of heat. That's how I knew there was a problem with my system. No cooling fan at all. I wouldn't let my wife drive it at that point, since I couldn't rely on her NOT to let it sit there and idle. Luckily, this was early spring, so it was still cold out.

Like I said, I tried different relays. I even ohmed out the ECT at different temps, getting readings that were within spec. You can find a lot out with some basic electrical theory and a multimeter.

The ECT works off of resistance (ohms), which the ecu reads and decides what to do. Simple enough, right?

Here is the strange part. I take a spent ECT and compare readings with a brand new ECT side by side, by taking resistance readings with different temperatures. A glass of ice water, and a glass of near boiling water. Each reads just about the same resistances each, yet one of them doesn't work correctly in the car.

So, this simple part can "test" good, yet still not function correctly. Major downer, since the car can overheat. Too bad there is no built in fail-safe for a bad relay or ECT. I bet there's a ton of blown head gaskets out there because of this.

Essentially, one needs to constantly be aware if there cooling fan is operating correctly or not.

KenC · Post by **KenC** » 09 May 2009, 12:48

Ok,

I think the T-stat may have been bad:

: T-stat.JPG (41.47 KiB) Viewed 1645 times

If you can't tell, the old one is on the left

Evidently he thought it more cost affective to just rip off the non-functioning t-stat.

OK, new t-stat & ECT sensor are in - man that's a tight squeeze to get the ECT in...

I've tracked down where the anti-freeze was gushing from. Here is a image of the hose connections at the firewall. These hoses are brand new (less than a week). The hose is still way loose, how do I fix this?

: Htr hose @ firewall.JPG (51.11 KiB) Viewed 1474 times

And, do I really need to use "Volvo" anti-freeze? It doesn't look like the good old green stuff, kinda' blueish. I don't know how much I lost (can't look down in the radiator) so I'm not confident in just topping off with water.

Thanks for the help!

Post by **vegasjetskier** » 09 May 2009, 14:36

Wow. The fan wouldn't come on and the car overheated, so his solution was to rip the guts out of the thermostat. Brilliant! It would take forever to warm up (if it ever did) when you wanted it to, and would overheat in stop-and-go traffic in the summer. Who could ask for anything more?

Post by **vegasjetskier** » 09 May 2009, 17:06

KenC wrote: Will check to see if the A/C clutch is engaging...what difference would that make?

It would indicate that the AC controls are functioning properly and your cooling fan should be running at that point. It's just a basic troubleshooting test to see if the fan will come on.

Post by **Ozark Lee** » 09 May 2009, 17:13

The hose is still way loose, how do I fix this?

Squeeze the clip and shove it in further. Those are replacement clips since they are yellow, make sure the old spacer isn't still in the hole, it will never fit and lock if the old stuff is still there. Been there, done that, got the T shirt.

...Lee

KenC · Post by **KenC** » 09 May 2009, 17:31

Spacer?

Messing around with it, I found an o ring and a yellow "washer" - both went on the copper stem inserted through the firewall - haven't looked further. Is it supposed to "snap" in there? It just kinda' pushes in, pulls out - no definite locking in there.

Any info on the anti-freeze - can I top of with the standard green stuff I have in the garage, or do I have to go to the dealer for their special brew?

Thanks!

KenC · Post by **KenC** » 09 May 2009, 17:46

Ok, maybe I got it this time. I felt in there and found detents on either side horizontally (obvious spots for the yellow retainer to lock into). I put the "washer/spacer" in first, then the o-ring, then put in the retainer which lock in. Then slid the copper tube in, and it seems to be in their firmly. I'm afraid I'm still used to "turn wrench until tight". I just wasn't sure if the assembly was supposed to be on the tube during insertion, or locked into the firewall first - then the tube inserted...So, did I do it right this time, or backwards?

Ok, still need to know about the proprietary anti-freeze or if I can use generic to top off...

Thanks!

Post by **vegasjetskier** » 09 May 2009, 18:54

KenC wrote: Ok, still need to know about the proprietary anti-freeze or if I can use generic to top off...

Thanks!

Here's a quote from MIJ:

Only replace Volvo coolant with Ethylene Glycol (the green fluorescent stuff). Prestone is pretty good (they even make a 50/50 mixture so you don't have to add distilled water to the more concentrated stuff), but best seems to be a phosphate free antifreeze made by Zerex called G-05, if you can find it in your area.

Post by **Matty Moo** » 09 May 2009, 23:05

I used prestone or peak extended life (NOT dex-cool). Phosphate free. I flushed all the old stuff out first, then added new.

I did a ton of searching on the anti-freeze thing. That was the general consensus.

You should track down the guy you bought that car from and at the minimum, beat his ass. I myself would take that t-stat, weld it to a pipe, and rape him with it.