I was driving my V8-powered 745 home from a Turbobricks meet yesterday, and just as I was pulling out of the parking lot (engine had been running for maybe 45sec?!?) I was gassing it a little and FFSSSHHHH, I hear a huge hissing/shooting sound and steam starts billowing out of the dashboard. I got off the road, switched it off and there was coolant dumping out the bottom of the car!! It was coming out the holes in the bottoms of the frame rails, from somewhere above the transmission...and tons of it was going in the passenger footwell. This was not a leak, it was catostophic coolant loss.

So, those of you who have had heater core experience on the 700/900 series, please help me out here. This is a terrible time for this to happen--I have no time to fix this, and no money to have it done. We're trying to sell this car. My inclination is to lop $1500-$2000 off the price and try to get it gone. How hard is the fix on this? My experience level is high; I did all of the V8 conversion work myself, including taking apart the dash to install the Ford EFI computer behind the glovebox. How much can I expect to be charged by a garage to have it done? IPD's heater core is $200; can I find a cheaper one? Finally, do you think this kind of leak is too large to be fixed by something like Alumaseal? This sounds like a burst, not a little leak, but I'm hopeful.

Anyone want a V8 Volvo 745 with a brand-new engine, running perfect and very fast, in gorgeous condition, for $7900, with a popped heater core? :(
--
FOR SALE 745 with Ford 5.0 V8, awesome car, 2300mi engine, email me

I'm not a mechanic, nor do I have many tools. I'm a stay-at-home mom who likes to tinker with stuff (the main reason for choosing my '85 760T). I printed out some instructions on replacing a heater core from the Brickboard, set aside a weekend without any family at home, then started taking things apart. Taking the seats out and placing firm cushions in the floor was a great help.

Prior to disassembly, my volvo mechanic let me pull a heater core from a salvage car being stripped of anything useful. I also grabbed some clean floor insulation and fiberboard pieces, as mine had been saturated with coolant through the summer. I took the heater box home to have as a reference for the "upcoming project." If I had known what I was doing from start to finish I think I could have done the entire job in one day. As it was, I took 1-1/2 days to complete the swap and reinstall the dash. At the same time I was also hunting for sources of water leaks that made the rear floor wet. In my dash re-assembly I failed to hook up a vac hose to the display, so my turbo gauge wasn't measuring anything, and I had an annoying hiss. To remedy this issue I again took things apart on a Saturday afternoon. At the same time I decided to replace my fuse panel and some relay plugs. The original fuse panel had cracked and turned brown around the blower fuse. Some of the plug-ins for the relays had melted a bit over the past 19 years. This job was continued over the next 2 days, in short time periods, since I was back to being mom/wife again. Making notes of what went where was helpful in this project.

If I can do this, never having replaced brake pads, overhauled an engine, etc., I bet you can. I found when preparing to re-assemble the dash, it was helpful to get away from working on the car, allowing time for thinking through the re-assembly before actually diving in. Sort of a zen thing, I guess. Anyway, I don't look forward to the time I have to replace the heater core in my husband's '88 740 but I know I could do it, given the right attitude and enough time without distractions.

Congrats many times over !!!! Thats a really difficult job. It's a great initiation though, and most jobs will seem easy in comparison afterwards. The only thing that seemed to come somewhat close was replacing my leaking power-steering rack using 2 simple jacks.

Replacing the heater core was my first job on my 85 740, and unfortunately for me I had to do it the dead of a New-Jersey winter. I only had one car at the time, so I had to make sure the car was driveable during the repair process. In my case it took 2-3 days to complete because, like you - my carpets, under-carpets, heat-insulating boards etc were all sodden with all the coolant I had been dumping into the system until I isolated the problem. So I had to also get those cleaned and dried - which was not easy at all. The coolant had used the ducts under the seat to seep into the rear-passenger-foot areas as well, so in my case I had to remove the front passenger seats, the ducting beneath, the rear seat and all the carpets (which first meant removing almost all the pastic moulding). I have this vivid memory of my living room full of drying plastic moulding and the smaller pieces of carpets. I wish I'd taken a picture of the metal floor of my car without the carpets - with all the wiring exposed. If you think a Volvo is noisy, try driving it without the carpets ! Handling all that coolant also caused the skin on my hands to flake off (not painful at all - but definitely something I wont forget).

Again - great job !

Noel

I replaced my heater core on an 85 turbo and it took a bit of time. The heater is really buried in there but the process is pretty simple...just time consuming because one must remove the lower dash console, I actually pulled my front seats out too (a couple bolts - the seat belt are a pain - but not req. though) and then the tricky part is getting to all the 8mm bolt heads that secure the bottom of the heater box, around it, and above it. I believe sealing strip is also required to seal up the box when reassembling. If you have a weekend you can do it. Just make sure to have some short screwdrivers and a 1/4 socket set with you..and remove the glove box and all lower trim, the radio too maybe to make it easier..and label any vacuum hoses you disconnect from the motors on the drivers side..I did this more that 2 years ago so I'm not keen on the details...if you did you're own V8 conversion this is a walk in the park..just a long boring one!

My friendly neighborhood Volvo tech tells me he can do it in about 4 hours, and you need an 8mm wobbly 1/4" drive socket. He also told me a lot of customers find it better to placer a 12V marine heater under the dash.

Figure 8-10 hours to repair this plus a heater core at about $115 (including shipping) from FCP Groton. Replacing a 700 series heater core is a time consuming job.
--
john

Are you sure its the heater core? Sudden, severe coolant loss sounds more like a ruptured/rotted/loose hose to me.

That was my reaction too, but I can't think of any hose that would dump coolant into the passenger footwell if ruptured. The heater core's nipples don't attach to the heater hoses inside the car--they attach on the other side of the firewall. The engine compartment was all dry with one exception--somehow, the front valance lip had beads of coolant on it! I have no idea how that could happen, but I need to look more.

It looks like I'll be selling it with the heater core bypassed. Of course I will advise buyers of this.

Of course you are absolutely correct. There are no heater hoses inside the passenger compartment. Don't know where my head was then. Probably up my a*s again :)

A loose hose worm drive clamp at the firewall will let coolant run down inside the driver's side of the passenger compartment on a 700 series. This will mimmick a minor heater core leak. Ask me how I know this.
--
john

Hi,

Sorry to hear of your bad luck! I just replaced the heater core in my '91 745T. Not a fun project. Not too bad, but very time consuming. I did most of the work with the help of my Vo mechanic when needed. Wouldn't be as scary if I had to do it again, but I certainly don't want to do it again. You won't be able to patch a hole that big. You could just block off the heater core (take it out of the "loop"), but then the car wouldn't have heat. You'd have to let any potential buyer know that if they wanted heat they'd have to replace the heater core. I'm not sure what it would cost to pay someone to do the replacement, but I think you'd be looking in the range of $1000 US to have an indy Volvo mechanic replace it. I'd say lop $1500ish off the price and try to sell it. If you had time to fix it, I'd say go for it, but the car would be out of comission for a while depending on how much time you could spend on it at once. Check the FAQ section for details on heater core replacement. Good luck!
--
Chris. Halifax N.S. '91 745Ti, 290K km and '91 745 NA, 380K km.