Bringing a 740 back to life

[Laird Scooby]

Originally Posted by Challo

Since the MOT managed a few local trips, but today took the old girl for a longer drive. Had the tracking done this morning, but it needs to go back as it pulls slightly to the left. Also there is some vibration at motorway speeds so will get them to check the wheel balancing.

Got back and noticed two issues to check on:

1. Start the car and it idles sub 1k rpm, but once up to temp and start in traffic in park it clicks up to 1100-1200k rpm. Any particular reason for this?

2. Coolant leaking inside and outside the car. Inside it’s the heater control valve, but I have the parts for that. Outside it’s dripping from the pipe which connects to the expansion tank. Going to replace that pipe, but not clear which one I need.

Checked PFV and they only have top or bottom hoses. I think I need top hose but unclear https://www.partsforvolvosonline.com...oducts_id=3950

Wheel alignment can be a pain to get right Chris, especially if the steering wheel has ever been removed for whatever reason. From the straight ahead position, you should have 1 3/4 turns to each lock or a smidge over but it must be an equal smidge both ways. If you haven't, they haven't aligned it with the rack central, just with the steering wheel in the straight ahead position which will cause it to pull.

You need 8mm bore heater (or fuel) hose if memory serves if it's the small hose from the expansion tank to radiator. If it's the other one, i think it's 19mm bore heater hose but remove the hose from the bottom of the tank and measure the size of the stub, will either be 16 or 19mm on the smooth part of it (don't measure the barb diameter!) so get whatever size it is.
The larger of the two hoses goes from the expansion tank to the bottom of the rad, the smaller (breather) hose goes to the top of the rad.

Thinking about it, you may not have a separate spigot for the small bore breather hose on the expansion tank, would help if you could post a pic of which one it is and how it's attached to the tank.

https://www.partsforvolvosonline.com...?cPath=608_683

A few options there to choose from!

Because you're losing coolant, you will have airlocks in the system, most likely where the temp sensor is in the head for the ECUs - this will cause a high idle. There could be other causes as well but you need to get the leaks sorted before going anywhere near those possible causes.

[Challo]

Cheers Dave. I’ll check the steering wheel point later and check if they have aligned it properly.

For the expansion tank hose see attached pic. It’s one single hose that runs from the tank to the radiator. You can see the leaks on the wheel arch.

[Laird Scooby]

Originally Posted by Challo

Cheers Dave. I’ll check the steering wheel point later and check if they have aligned it properly.

For the expansion tank hose see attached pic. It’s one single hose that runs from the tank to the radiator. You can see the leaks on the wheel arch.

That appears to be leaking where it attaches to the bottom of the expansion tank Chris? If so, remove it from the tank and inspect the end (measure the stub while it's off but seeing that, i'm 99% certain it's 19mm) and you'll likely find the end has perished. If so, it's long enough that you can cut the end off (it's only 1/2-3/4") and refit with a new Jubilee clip as a semi-permanent repair while you source some 19mm bore heater hose - may also be sold as 3/4" bore heater hose.

The people who did the alignment won't have removed and refitted the steering wheel, if the straight ahead position is wrong they would have simply aligned it to that, even if the rack wasn't central. Because it's PAS, any position other than dead centre will mean the spool valves in the rack are opened up so will be subject to hydraulic pressure from the PAS pump which will make the rack move towards whichever way is slightly off-centre. It will also bol your PAS fluid so it will froth up and bubble out of the breather in the PAS reservoir, not so bad with a remote reservoir but if yours is like mine and the reservoir is integral with the pump, causes problems!

[360beast]

Originally Posted by Challo

Cheers Dave. I’ll check the steering wheel point later and check if they have aligned it properly.

For the expansion tank hose see attached pic. It’s one single hose that runs from the tank to the radiator. You can see the leaks on the wheel arch.

The nut holding the front bumper shock absorber to the chassis rail is missing.

[Laird Scooby]

Originally Posted by 360beast

The nut holding the front bumper shock absorber to the chassis rail is missing.

Dalmatian! Well spotted Luke! Looks like the bolt has sheared if you enlarge it enough..........

[Challo]

Originally Posted by 360beast

The nut holding the front bumper shock absorber to the chassis rail is missing.

Thanks. Had a look and the thread is ok. Just need a new nut.

[bob12]

Originally Posted by Challo

Cheers Dave. ................

For the expansion tank hose see attached pic. It’s one single hose that runs from the tank to the radiator. You can see the leaks on the wheel arch.

Some years ago I had great difficulty in finding that hose (Volvo Pt No 9155496) but found a German firm Autoteile-Luecke who had the extact part made by URO (under the same reference). A-L are main agents for URO. People decry URO but, in respect of this particular item I have to say it appeared well made and has lasted 7 years so far!

I have just looked A-L up and see they now have a shop on eBayUK where the part (Radiator Hose, Cooling 9155496 suitable for Volvo) is currently listed for £26.70 at:

https://www.ebay.co.uk/itm/382954642...Cclp%3A2047675

In 2015 it was £10.73!!

Bob

[Laird Scooby]

Nice find Bob!

Added to my watch list as it also fits mine.

*** EDIT *** Just cross-referenced it on Rock Auto - £2.74!

https://www.rockauto.com/en/parts/%C...oir+hose,11576

Made by ÜRO PARTS apparently........

[bob12]

Originally Posted by Laird Scooby

Nice find Bob!

Added to my watch list as it also fits mine.

*** EDIT *** Just cross-referenced it on Rock Auto - £2.74!

https://www.rockauto.com/en/parts/%C...oir+hose,11576

Made by ÜRO PARTS apparently........

Well, I know where I would get it from then Dave .... no competition!!!

Bob

[Laird Scooby]

Originally Posted by bob12

Well, I know where I would get it from then Dave .... no competition!!!

Bob

Definitely Bob! Even with S&H, exchange rate commission and HMRC - errr, no, not HMRC as the sale value is under £15 so just S&H and exchange rate commission it should still be much cheaper.