1997 Volvo 850 GLT Coolant Question

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1992 - 1997 850, 850 R, 850 T5-R, 850 T5, 850 GLT
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1997volvo850
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1997 Volvo 850 GLT Coolant Question

Post by 1997volvo850 »

I recently went to take my 1997 Volvo 850 GLT for a drive and the coolant light came on.

I immediately got out and checked the coolant reservoir. It was empty. The car does seem to lose coolant over a period of several months but I've never seen anything like this. I did not see light on last time I drove but others have been driving this car recently.

I added about a half gallon of coolant to overflow tank and it drained right into engine. Nothing leaking on ground. I mixed up another half gallon of coolant and it drank it right up. Overflow empty. Nothing leaking on ground. Then I added the 0.5 gallon of distilled water left from mixing new coolant and another gallon of distilled water and the overflow tank is still empty. Nothing flowing onto the ground.

I understand the 850 is supposed to take 2 gallons to top off the 850 coolant system. At this point I suspect the worst but want to seek advice from this group.

My family members have been driving the car lately (over last week). They swear that the red coolant light never came on. Due to car issues they have been driving the 850 on a regular basis for about a week so I have no reliable information about any issues. Coolant clearly not an issue according to them though coolant seems to be completely missing from engine. It difficult to image they drove the car for long without coolant. Wouldn't the engine melt down and die? Or could they drive it 20 miles to work and back without killing engine?

Years ago there was an issue, likely due to coolant mix, where the coolant would boil over when I parked the car. I mean the car would run fine all day and when I parked the car the coolant boiled over. This was addressed by a garage a few years ago. I did not see any signs off coolant in the driveway though we have had significant rain over the last week.

The car starts up and sounds normal. I don't leave it running since I have no idea where the coolant I'm dumping in is going.

I stopped adding after almost 3 gallons. I wanted to check here before proceeding. Please advise.

Thanks in advance.

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Post by Liggywuh »

Hello!

The coolant is clearly going somewhere, but you already knew that. If you can't see where it is going, and the system is not filling up I am guessing it might be a dodgy heatercore or o rings around it.

If you pull up the carpet in the driver and/ or passenger footwell, is it wet? The heatcore sits low down behind where the radio etc sits, and has 2 hoses (one in, one out) from the engine that passes through the firewall, and then down (and back) to the heatercore.

It sounds like you have a bad leak there, and therefore you are not filling up the system (which would also explain why you can't see it running onto the ground).

As for a 20 mile trip with no coolant in the engine, I would cross my fingers, but I really hope your head gasket is not toast!

Good luck!
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1997volvo850
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Post by 1997volvo850 »

I do see a small wet spot on the driveway under the center console where the heater core is. Carpet under passenger carpet is damp. Not what I'd expect after adding gallons of water. I will add a few more gallons of distilled water to overflow tank as soon as I buy more.

Options for diagnosing leak as heater core versus o-rings. Is it enough to pull back the center console, add water, and watch whether water escapes near o-rings or from heater core itself. Or is it possible both heater core and o-rings are bad?

Options for repair: 1) tow to garage 2) fix it myself (depends on level of difficulty) 3) Macgyver hoses and drive car to garage

Is it possible to temporarily fix/clamp hoses to facilitate driving to garage? I believe I've read about folks clamping the hoses. I'm not clear whether this damages the hose and imposes additional expense.

I will look around for instructions on this repair to see how difficult/time consuming it is. Any pointers to reviewed tutorials are welcome.

Thanks again.

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Post by abscate »

Pull the dipstick and check the crankcase and transmission for signs of milkshake.

Yôu can’t drive 20 miles without coolant, you will make about 1/2 mile.

My guess is heater core leak, which is easy and cheap to fix
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Post by rguzz »

As Abscate has pointed out a few times in the past you can dump lots of coolant in the passenger side foot well without soaking the carpet. The thick matting underneath will soak it up before you notice wetness on the surface. Not to say it isn't leaking from some other location but this is a well recognized place to look for "occult" coolant loss. Does it smell like coolant inside? If it's heavily diluted maybe not much.

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Post by 1997volvo850 »

I haven't opened things up yet as I'm currently reading up and watching videos on heater core replacement. Robert's videos give me confidence to consider fixing this myself. Sadly, I think I've watched his heater core video before just for fun, like many of his other videos. My main concern is scope of repair.

It seems this DIY heater core repair could easily become much more complicated, time consuming, and expensive if I need to replace the metal coolant lines coming in from the firewall to the heater core and/or possibly the coupling where the hoses connect through the firewall.

Given the massive amount of experience here I'm wondering about the probabilities of replacing only the heater core, or heater core plus pipes, or heater core plus pipes plus coupling. Do folks tend to replace just heater core? How often do pipes fail? coupling?

I'm getting ready to order parts. Given ordering and receiving parts take days I want to make sure I look for issues with these other items before ordering the heater core. I'd like to avoid the "install heater core, leaking via pipes, rip apart, order pipes, install pipes, etc."

I'm planning to open things up this morning. I'm wondering if removing the heater core tends to cause problems with pipes/coupling as in things are brittle and just messing with them causes additional failures. Trying to learn as much as possible before proceeding.

Thanks in advance for the help.

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Post by Liggywuh »

Hello again!

I will be doing this job next year on mine as preventative, not because of a leak (I think the parts on my 99 are original, I had to replace the radiator and did some hozes at the same time).

I will be using *at least* new hozes to and from the engine (to heatercore), new core and new o rings. I will probably do the metal pipe from firewall too, just because but I don't think many people have had problems there.

The best bet is to look where the leak is.

I think most people have either busted o rings or the side of the heatercore has started to weep. My radiator had started to weep on one edge, which was why it got replaced.

EDIT:

If the core or o rings are damaged, I would guess that the hozes might not have a lot of life in them, again, thoroughly inspect them before you decide not to replace them.

Check also for the milky fluid in the oil system, if the headgasket is already toast then you probably don't want to spend a lot of money on a new heatercore etc to then have to swap the headgasket and the associated work that goes with it.
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Post by abscate »

Those hoses are really high quality and rarely fail. Replace every oring on both the bulkhead and the heater core connect with genuine Volvo parts and you should be fine.

OEM Volvo only on cooling hoses and connectors. It’s one of the few places we judge here :D

You can also run straight water for a week or two, no coolant, if you aren’t on the highway in the heat , just local low speed driving until you get all your parts in over two weekends. Not in winter , of course.

FCP IPD eEuro all carry them

https://www.fcpeuro.com/products/volvo- ... -3545662oe
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Post by 1997volvo850 »

My old heater core just doesn't want to come out. The rubber condensation drain is in a bad spot. Doesn't just rotate nicely like in the three videos I watched. Then again I don't like forcing things so I'm a little on the cautious side. I'll have an update once I manage to get it out and take a look.

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Post by 1997volvo850 »

Houston, we have a problem:
IMG_0166.JPG
I'm pretty sure I know where all of the coolant I've been adding is ending up:
IMG_0175.JPG
I noticed the coolant flowing back along the top of the center console hump. The back seat floors were flooded with coolant. The front driver and passenger floors not so much.

Note the long crack along the bottom of the heater core. Also note the darkened discoloration an inch or so up from bottom of heater core grill. I suspect this discolored area may indicate another leak and be responsible for the long-term slow coolant loss I've noticed in recent years.
IMG_0177.JPG
I'm hoping these line connections will clean up ok:
IMG_0174.JPG
I checked oil and I don't see milkshake so I don't believe the head gasket was destroyed. It's possible the heater core was destroyed by the pressurization that happens when I stop the car. I suspect this has something to do with the fan not staying on after the car is shut off.

I have another 850 that hasn't run in four years. I'm not sure about taking the heater core out of that one. I suppose I could try it?

The old heater core has '96' on it. I suspect this is the original heater core. They just don't build things to last anymore. :^)

I'm thinking to order a new Behr heater core. abscate recommends replacing the o-rings that attach the coolant tubes from heater core to coupling on firewall. I'm thinking to do this as long as folks are confident the coupling will survive my messing with it. I want to avoid scope creep (IT term).

Thanks again for all the help. I need to decide whether I should scavenge heater core from other 850 or just go ahead and order new one. I'm sure the experts here will set me in the right direction.

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