1998 V70 T5 Very Strange, Rough Start

[villagepc]

As a budding Volvo mechanic - you may want to invest in a bluetooth ODB scan tool - ELM327, and pair it to your smartphone (if you own a smartphone).

I bought the blue one that you see floating around on ebay for 10 bucks or so, and its performed well with both android apps Torque and ODB Car Doctor.

You'll have to see if there are IOS versions (apple) since I don't know. With those apps and odb scanner, you can pull the codes from the computer to determine why your Check Engine light is on and where to start looking for the problem(s).

Changing the thermostat and ECT are pretty straight forward, and the write ups here are excellent.

[WagonLagan]

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.

Awesome, thank you.

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

Was going to ask a question about this because I'm not sure how much I trust my hoses (they're old and degraded. They're on the to do list after all that I've learned today!) However I stumbled upon this confirmation of why not to do it:

... never, ever, try to use the drain cock to drain the radiator. Nine times out of ten it will break and then you are looking at a new radiator.
...Lee

And I sure don't want to buy a new radiator, so I'll take the chance with the hoses. Thanks again. Might have saved me another horrendous repair bill.

I've never done anything around the radiator before. I'll take a peek tomorrow to make sure I can identify the radiator hoses you're talking about.

Heading off for the night, will be continuing my research tomorrow. Thanks very much everybody: Misha for answering all my specific questions and sharing all of those awesome insights! Showell for your confirmation and additional thoughts. Villagepc, thanks for the idea. I've been wanting to get a code reader, and hadn't considered a blue tooth/smart phone one.

One last question if anyone knows off the top of their head: What is the part number, or how can I identify that hose that runs to the ETC? The one that sits next to the power steering fluid container. Can't seem to find a number or name for it, and I want to replace it while I'm at this.

Thanks and have a great evening all!

[misha]

For access to a lower radiator hose you will need to remove the plastic shield from under the car.

Good luck!

[E Showell]

I have successfully used the radiator petcock drain with no problems in the past, but I'm going to suggest an alternative that is much less of a hassle. You don't need to completely drain the coolant to change a thermostat. Instead, I've had success just emptying the overflow tank with a turkey baster or the equivalent. Drain the expansion tank into a clean container and you can reuse the coolant you remove. If you empty the expansion tank, you can remove the thermostat housing with very little coolant loss/spillage. In my view, it is much simpler than draining the coolant to perform this repair.

Misha -- as far as cutting the wires to the ECT go, I had to cut mine to get access to the plug. You may not have to do that.

[villagepc]

Here's a couple of threads regarding vacuum lines.

https://www.matthewsvolvosite.com/forums ... f=1&t=6941

and hard starts

https://www.matthewsvolvosite.com/forums ... 9&p=308705

hope it helps

[WagonLagan]

I don't suppose that low coolant could cause these problems too? I just noticed when I went out that my coolant was basically at the minimum level, though I haven't seen a low coolant light (if there is one?).

Going to grab some coolant today, and I guess I'll just add some and see if that changes anything.

[misha]

No,but if there are no visible leaks and you still loosing it...it's a problem.

Check oil level.

There is a low coolant level light,but turns on when coolant is a tick under min mark at expansion tank.

[WagonLagan]

Glad I can take the low-coolant off the list. Thanks!

Oil is just at the min mark when cold. I'll add a little extra unless that's where it's supposed to be when it's 20-30F.

Had a terrible oil leak from the PCV system and did that service a couple months ago. Knocked out the big oil leak, but I'm pretty sure I have at least one small one yet.

From what I've read here, looks like Zerex G-05 is the preferred coolant? Will probably do a distilled water flush while doing all this, and put new coolant in.

[WagonLagan]

Hey all.

Got my parts and will be doing this project tomorrow.

I would REALLY appreciate if anyone had the time to answer these two questions.

Should I attempt to drain the engine block coolant as well? I know that drain plug is brass and not dangerous to remove. However, I wonder if the double distilled water flush I plan to do will be sufficient in clearing that out without directly draining the engine block coolant area each time as well?

So far everyone seems to agree I should try draining it via a hose rather than the radiator plug. I've seen two videos that both do it via the drain plug, but that's probably because they're more experienced than me. I'm going to attempt draining it via the hose since the prospect of damaging my radiator scares me. Should I expect the fluid to shoot out, or trickle?

I really appreciate it all!

[misha]

Before you drain the old coolant,drive the car a few miles allowing the engine to get up to operating temperature.Then remove the lower radiator hose and wait it to drain.You can remove expansion tank cap which can speed up the draining process and help that all of the coolant drain.

After it is drained....attach lower radiator hose,fill the expansion tank with 50/50mix of coolant & tap water,start the engine and wait for cooling fan to kick in with expansion tank cap removed and keep the eye on coolant level in the tank all the time.Top up in the process if necessary.

When cooling fan stops,turn the engine off,check coolant level,top up if necessary and that's it.

In the next few miles you should have a low coolant light.Stop,top up the coolant tank up to proper level and that should be that.

The whole system should have around 7.3l of coolant.

Good luck!