1998 V70 T5 Very Strange, Rough Start

Post by **WagonLagan** » 19 Jan 2015, 11:11

Last night, I went to start my car and it gave me a very hard time.

I wasn't really sure how to describe it, so I tried starting it again this morning while recording, and it showed the exact same behavior.

From the first attempt at starting, the fan is running, and continues to run for awhile after I stopped trying. You can just barely hear it with the volume up somewhat.

This video is from a cold start after sitting overnight. It is cold here, sometimes 20-30F or lower, but it's been starting just fine until yesterday.

The only issue I've had that I can think may be related is that interior lights and headlights dim when I turn something on such as the heater.

Check Engine light was on already, so I don't know if it's throwing new codes or not.

Lastly, it doesn't usually idle that high. It usually idles at around 800 rpm.

VIDEO:
https://vid.me/n4sr

Unfortunately, this is my only means of transportation, and I am very concerned that it isn't reliable to drive right now. I really hope that I can get it fixed before Friday, or getting to work is going to be a challenge.

Hoping that somebody will be able to help me determine what is wrong with it so that I can attempt to fix it.

My limited knowledge makes me wonder if this is a temperature sensor or something similar, since the fan is coming on and staying on even though it's very cold outside. I had noticed that the fan was running more often lately before this occurred.

I also found this post: https://www.matthewsvolvosite.com/forums ... =1&t=59783
Which had some mention of temperature sensors, RPM sensors, and fuel pumps.

I greatly appreciate any suggestions or direction you can share. I'll be happy to provide any information you may need to help narrow it down.

Thanks very much to anyone who can give me any insights.

Post by **misha** » 19 Jan 2015, 11:31

If cooling fan kicking in before starting and if it works even when you turn off the engine...your ect is bad.

I guess that ac is off in this case.

Secondly....when you're starting the engine WHY you don't wait for 2-3 seconds after turning the key in position II,letting the fuel pump to prime the fuel before starting?You must do it before every start.

Post by **E Showell** » 19 Jan 2015, 12:23

+1 on bad ECT (engine coolant temperature) sensor. Make sure you change the thermostat at the same time and go OEM Volvo on this one.

Post by **WagonLagan** » 19 Jan 2015, 15:43

misha wrote:... when you're starting the engine WHY you don't wait for 2-3 seconds after turning the key in position II,letting the fuel pump to prime the fuel before starting?You must do it before every start.

Wow. Thanks misha, I had no idea about that. I'm a very amateur mechanic and never had anyone car-savvy to teach me proper care, so I have a lot to learn. Really appreciate that tip, I'll make that a habit!

misha wrote:If cooling fan kicking in before starting and if it works even when you turn off the engine...your ect is bad.

E Showell wrote:+1 on bad ECT (engine coolant temperature) sensor. Make sure you change the thermostat at the same time and go OEM Volvo on this one.

Awesome. Thanks a lot you two.

1.) First, is there ANY way to drive around safely right now? If I unplugged it for example, would that be a temporary solution to get the car to run at least get the tools and parts and back? Or will it drive safely as is, and just start weird?

Also, it looks like Robert has a great video walk-through (as usual) here:
And I found some other write ups with good information.

2.) Any other thoughts on this job? I've never drained coolant or any engine fluids before, so that's a bit intimidating to me.

3.) To confirm, these are the parts I need, correct?
ECT: Part #: 9186486 Example Here
Thermostat: Part #: 271417 Example Here

4.) Lastly, I found this post: https://www.matthewsvolvosite.com/forums ... p?p=354476
So from what I understand for the thermostat, I should get an 87C as my car is a turbo, or a 90C if I can't find the 87C since the difference is negligible?

Thanks very much for any thoughts, especially on if it's safe to drive my car for a couple days while I get the parts and tools!

Post by **misha** » 19 Jan 2015, 16:02

Don't go with 90+ degree thermostat on turbo engine.

87 is the one you need.

Draining and filling the coolant is not a big deal.But you need to properly remove trapped air from the system.

Read carefully about how to safely unscrew thermostat housing bolts and not to round them.

There is a plenty info and write-ups on the forum.Take your time for reading and learning and you can't go wrong.

Don't unplug ect,it could happen that it will not start at all.

Post by **WagonLagan** » 19 Jan 2015, 16:08

Thank you for the quick reply and all that info misha!

Two last questions if I'm not asking too much of you.

1.) My limited knowledge so far seems to indicate to me that it is safe to drive like this, and will just give me some trouble starting and maybe idle high. Is this accurate?

2.) How does one properly remove trapped air from the system? Or if you expect that will be included in one of the write-ups, any specific one you'd recommend? (Edit: Found this write up that looks pretty thorough. Is the process you're referring to filling it to max, driving it around, then checking again as cn90 talks about?)

Thanks so much again, you've really helped me out.

Post by **E Showell** » 19 Jan 2015, 16:13

Please, please, please -- check the connector for the ECT before you cut the wires (don't ask me how I know this. . . ). Last time I changed the ECT, I cut the wires first and checked the connector second. The connector was loaded with corrosion - so much so that had I used electrical contact cleaner and dielectric grease, I might have saved the original. It was not clear whether the actual sensor was bad or the corrosion was interfering with proper readings.

Post by **WagonLagan** » 19 Jan 2015, 16:16

E Showell wrote:Please, please, please -- check the connector for the ECT before you cut the wires (don't ask me how I know this. . . ). Last time I changed the ECT, I cut the wires first and checked the connector second. The connector was loaded with corrosion - so much so that had I used electrical contact cleaner and dielectric grease, I might have saved the original. It was not clear whether the actual sensor was bad or the corrosion was interfering with proper readings.

Thanks Showell, I'll check that out. Who knows, could save me $55! Really appreciate the idea

Post by **misha** » 19 Jan 2015, 16:23

Not at all.

1.The car will run rough,fuel mileage will be very low.It's not advised to drive it in the long run,but a few miles would not hurt anything.

2.After you replace coolant with 50/50 mix with antifreeze & tap water and top up to proper level on the expansion tank(around 7.3l),the engine must run untill cooling fan kicks in.Monitor the coolant level all the time.It must always be at proper level.Cap must be removed from the tank while this is happening.After the cooling fan kicks in and finish,turn off the engine,check the coolant level and top up if necessary.

You should have one more low coolant light in the next few miles after this procedure,so keep in the car a little more coolant to top it up to a max level.

When you drain coolant,do not remove plastic plug from the radiator.It can broke.

Instead,loose a lower clamp and remove a hose from lower side of the radiator and wait for coolant to escape.

Before you drain the old coolant,warm the car to operating temperature.This will allow thermostat to fully open and all of the coolant will be drained from the radiator and block.

Post by **misha** » 19 Jan 2015, 16:25

E Showell wrote:Please, please, please -- check the connector for the ECT before you cut the wires (don't ask me how I know this. . . )...

WHY he would cut the wires from ect?