Dear Fellow Brickboarders,

May this find you well. I just received a set of heater hoses for 93 940 from Borton Volvo in Minneapolis.

The hose into which the heater control valve fits, is made in Norway and looks to be perfect.

The return hose, made in France (Part #3507413) may be problematic. At the end of the longest section, there is a 3" "arm". Just after the bend, there is a ridge in the rubber, that runs parallel to the length (rather than around the circumference). This ridge is perhaps 1 1/4" long (it ends about 1" from the end of the hose) and about 1/16" high.

It appears as if a layer of reinforcing ended short of the end of the hose.

The other one that Borton had on the shelf was exactly the same.

If anyone has installed OEM Volvo heater hoses recently, did the return hose have this ridge at one end? Or, was the hose even (uniformly smooth) from one end to the other?

It is possible that the machinery was out of adjustment, and produced a batch of hoses that are not up to spec.

Given:
(a) the difficulty of installing these hoses
(b) the rapid coolant loss that occurs when they fail
(c) the possibility that the failure could be a couple of years down the road, but still far short of the normal working life

I'd sure like to find out if this hose has been made correctly, or - on the other hand - if it is defective.

Thanks for your help. I'm much obliged.

Yours faithfully,

spook

Hello Spook

I have two Volvo heater hoses, same part number, made in France though, same bump as you described, extending to the bend. The last 1 1/4 “ for the tube or heater valve is perfect. I would not worry about it. I really never would have thought much about it.

When you replace the hoses, and if you’re going to replace the coolant, flush the engine after removing the t-stat. Also open the block drain. Flush out the heater core with a hose attached. The copper tubes coming out of the fire wall are very soft, so be careful there. Don’t attempt to pull or twist those hoses. You will have to carefully cut the hoses lengthwise there.

One of the toughest jobs is removing and reattaching the hose to the block under the manifold, without removing the manifold. I kind of twisted it by hand, and then wedged it out with a screwdriver through the manifold.

I used a little sensor safe silicone as a lubricant at some of the tube ends just to make it easier to slide the hoses on (especially at the tube under the manifold).

Good luck
--
Tom F. Three 940s. One down. Mods, RainX. Lien holder on two more (the kid's). Rust In Pieces, '78 245

Dear Tom,

Good p.m. For how long have the French hoses been in place? I'm wondering if that ridge is a manufacturing defect, that compromises long-term serviceability.

Thanks for the "heads-up" about the hose ports on the firewall. I will use an
X-acto knife carefully to cut the rubber paralell with the copper tube's axis. I may make two cuts about 30 degress apart, so that the hose will come free easily. Those ports are relatively accessible, so that should not be a problem.

I'd like to flush the cooling system. What is the proper sequence?

For example, should one:
(a) drain the coolant by opening the drain cock
(b) re-fill with water
(c) let the engine get to operating temp (so get clear water to the heater core)
(d) let the engine cool
(e) drain the clear water (dirtied by what's inside the heater core)
(f) close the drain cock
(g) change the hoses
(h) re-fill with coolant/water (50/50mix)?

Some further questions:

(a) Can dishwashing liquid be used as a hose installation lubricant?
(b) Is the head hose port stronger than those on the firewall?
(c) Must one cut the hose length-wise, to detach it from the head hose port?
(d) Can one grip the hose and pull it free of the head hose port?

I'd hate to snap the hose port from the side of the head!

Thanks for your insights.

Yours faithfully,

spook

I’d bet that flaw is in every Volvo brand heater hose and it is minor enough not to cause a problem. I am also not convinced that it is a flaw, but rather a manufacturing process.

For flushing, I just blasted the garden hose into a connected cooling hose and let the water poor out where it wanted. No science, just blast it. Example, put the garden hose in the heater core hose and turn the water on full blast and let it come out the bottom hole or hose. Keep the engine drain open all the time. BTY both the Nissen and the Blackstone radiators have drains cocks. Do the same for the radiator. For the engine I blasted most of the water into the hose that leads into the T-stat housing.

There is no need to start the engine during this process unless you are using a “coolant system flush/cleaner” product.

Now rinse out the hose water with a gallon of distilled water.

The hose connection at the head under the manifold is very robust unlike the tubes going into the firewall. You can get three fingers from each hand on it. You can hold the clamp with two fingers and tighten it with a screwdriver. But you cannot get a grip in it. You can break the seal by twisting and using a little shearing action with a screwdriver from above.

Detergent to aid in hose installation, not sure if that is a good idea. A very light smear of silicone will harden and will not contaminate the coolant.

Refilling: After you get all the hoses on and drains closed; pour in 50% of the system’s capacity of UNCUT coolant. Fill the engine first through the T-stat housing. Install the T-stat, air hole up, and it’s cover and pour the remaining coolant into the overflow tank. Reasoning for using uncut coolant is that you do not know how much water is remaining in the engine and other parts. If your system capacity is 10 quarts, add 5 quarts of uncut coolant and then top it off with distilled water. This insures a 50-50 mix. (If you were doing this in the winter, I’d top of the overflow tank with a 50-50 mix.)

Warm the engine with the heater on until the T-stat opens. Top off the coolant with distilled water after it has cooled.
--
Tom F. Three 940s. One down. Mods, RainX. Lien holder on two more (the kid's). Rust In Pieces, '78 245

I recently installed a set of heater hoses on my '93 944ti that I purchased from my local Volvo dealership, they did not exhibit any such abnormalities. I also installed hoses on my '85 745ti last year, these are the same hoses, they also did not exhibit such abnormalities. If I were you I would take the hose in question back to the dealership and ask for a replacement, they should be happy to replace it for you.

Dear John,

Good p.m. and hope this finds you well. Thanks so much for your report. I bought these from Borton Volvo in Minneapolis. Jon Reynolds looked at another on they had in stock, and it was the same as they sent to me, i.e., with a ridge. That could mean there is a batch of hoses, that are "off spec".

Thanks again for sharing your insights.

Yours faithfully,

spook

Spook, the aftermarket ones I put on from Groton did not exhibit any such anomaly, where quite perfect. I was not the only one who suggested you go that route.

Dear Park,

Good a.m. and may this find you well. When it comes to "mission critical" parts, I try to err on the side of caution. A "mission critical" part is one, which if it fails, ruins the engine, transmission, rear end, or some high-value item, or compromises safety in a collision (e.g. body panels, seatbelt parts, airbag parts, etc.)

If I know that an aftermarket part was made by the same firm that makes the OEM part, I'll cheerfully use the aftermarket part. The reasons:

(a) The part likely was made on the same production line, using the same materials and process. It it is very expensive to have two production lines for the same item and only slightly less costly to produce batches of parts, made to slightly different specifications.

(b) There is no magic in having "Volvo" inscribed on the part.

However, if the aftermarket part comes from a firm - other than the one that made/makes the OEM part - there is simply no way to know to which specifications it has been made. As a result, one is making a leap of faith. I'll do that, if the part's failure does not have ruinous impacts.

Thus, if I owned a 960, I'd be sure to use genuine Volvo timing belts exclusively, because a 960 timing belt breakage ruins the engine (or at least most of it).

On a 940, I can use an after-market timing belt, because a timing belt breakage is inconvenient, but does not ruin the engine.

These heater hoses are:
(a) timing consuming to install
(b) can quickly lead to engine failure, if the hose ruptures (and one does not shut down the engine at once).

I deem these hoses to be mission critical parts.

Thus, I was trying to err, on the side of caution.

I'll await further comments.

Yours faithfully,

spook

Spook you are jewel.