1998 Volvo S70 GLT Overheating RESOLVED ECT

Post by **rspi** » 18 Jul 2013, 02:37

precopster wrote:At steady 30mph on flat roads on a cool to mild day it just dropped from 99C to 90C so a good difference.

Can be the difference between a boil and non-boil. It's a smaller area than a radiator but still capable of sending off a lot of heat.

What if you are just sitting idle?

Post by **precopster** » 18 Jul 2013, 02:55

Even better as temp increases to around 101-102 deg which is over boiling point if tap water or poor quality coolant is used. However the heater lowers it to around 94-95 because the radiator isn't helping as much by having air flow across it.

Post by **erikv11** » 18 Jul 2013, 09:33

Teslacoilftw wrote: ... I don't own a fuel pressure gauge. I'll look into seeing how much they cost. Or is there another way to test this theory?

You can also use a two dollar tire gauge. It will get ruined by the gasoline, but it will work for a couple tests.

Teslacoilftw · Post by **Teslacoilftw** » 19 Jul 2013, 21:33

Let me clarify some things. The overheating is after I've been in Heavy Seattle Traffic on 405 for hour +. The Fan does come on but when it's overheating I can tell that it's not coming on at all. I've seen it come on Randomly without the AC on. (working correctly) it does in fact sound like its on Full blast. The over heating problem is random as in not always. The first day I changed the Sensor out.. I was stuck in Traffic for an hour + and didn't have any issues. The following day.. I had the problem. I'm assuming that if the water pump was failing It wouldn't circulate at all and therefore overheat All the time and it doesn't. I'll try the Tire gauge I have 1 laying around... How should I test this? Just Use my phone and Count down from 20mins and see how far it drops? The Starting problem is also random ... Sadly this is the story of my life... unfortunately.... Things are randomly which prevent me from taking it to a mechanic and then I can't show the problem. Car Starts up some days no problems no sounds. Other days Its Groggy and it's died. If I start it and give it a little gas it evens itself out and sounds normal.
Thanks Everyone who has replied!

I don't have any issues at Idle.

Post by **precopster** » 19 Jul 2013, 21:53

If you took your car to a mechanic and he then got on the phone and rang all his buddies to ask them what they thought the problem could be instead of pulling out some diagnostic tools and taking some measurements would that instill confidence? Rhetorical question I guess but you do see my point?

You're really not going to get anywhere with this unless you take some sort of reference at some point. That's why I suggest getting a scan tool and having it connected while driving. It can monitor coolant temps for you and you can use your ears (with a/c off) to hear the fan coming on and reference that to the coolant temperature.

The first item in my list would be the fan relay and I would change it out quickly. Aluminium heads don't take kindly to overheating. Two or three mild overheats and you have enough warp in the head to cause gasket seapage.

One serious overheat and they're well and truly done.

Post by **abscate** » 20 Jul 2013, 03:35

Go over your fan wiring and relays carefully, cleaning every contact and testing relay function. Look online for wiring diagrams to guide you.

MVS respects all copyrights and urges you to do same.

Post by **mikealder** » 20 Jul 2013, 06:14

You can get the wiring diagram you need by clicking Here Page 19 or 20 depending upon engine management - Mike

Teslacoilftw · Post by **Teslacoilftw** » 23 Jul 2013, 19:01

So I recently changed out my Fan Relay from one I got from a Junk Yard. I haven't driven it much but I can say this... I haven't had any issues recently with starting and I have heard the Cooling fan come on a few times as it hits Temp. There again the problem wasn't always and it's been random the last last few times it did happen so we will just have to hide and wait.

Thanks everyone who has posted info. Greatly Appreciate the Wisdom that has been provided!

Teslacoilftw · Post by **Teslacoilftw** » 01 Aug 2013, 21:04

So a quick update. It's not fixed. The Fan isn't coming on like its suppose too. It's coming on Randomly. Looks like I'm loosing Coolant. Its not going into the oil. The oil level has remained the same and I'm not smoking out the back. In the last week I've had to put in about 5Gallons of Fluid back into the System. Sporadically throughout the week. If the coolant isn't going into the oil where would it go?

Post by **abscate** » 02 Aug 2013, 04:52

Iffy fan relay and iffy fuel pump relay would cover both experiences? These are both known parts to fail at high mileage. I would replace both.

1998 Volvo S70 GLT Overheating RESOLVED ECT

Re: 1998 Volvo S70 GLT Overheating