So i finally got my 1994 S10 Blazer back and now i think that the heater core is leaking. I noticed a sweet smell coming from the car when the defroster is on and then today when at the junk yark i picked up my tools from the passenger floor and they were alittle damp. I put a can of stop leak in it, hopefully that will do some good, but wont know for sure.

Has anyone replaced a heater core in a 1st Gen Blazer and if so how hard is it to do and what is required.

 

It's easier to do on a 1st gen than it is on a 2nd gen!

I think that the over the counter repair manuals cover this quite well. You'll definitely want a reference handy while doing the job.

 

Yea, i have a Haynes generic 83-94 Blazer S10 manual so i was gunna take a peak tomorrow. Odd thing just happened i was sitting at idle for about 2 mins and then noticed my temp was up around 240. Sped up to about 50mph then put her in neutral and it slowly dropped. Came to a red light and left it in neutral and then it dropped back down to 200-210, very weird

 

It's pretty easy to do. Read this link to give you some idea on what's needed. I've swapped 3 of them. Also always test your new core, something my dad always taught me to do. Glad I did recently cause sure enough the new core I was about to replace had a very good size leak. I just filled it up with water, capped one end and blow on it.

 

so i'm not the only one who does that.

these 1st gen's can be done in the dark, with one hand tied behind your back, they're so easy. yes i've done quite a few, but believe me, even for your first one, you'll be amazed after you're done how easy it was.

the only thing i would stress to you is, if your truck has A/C, make sure you pull out the dash far enough to ensure the pipes go through the firewall with out any twisting/sideways pressure. this will more than likely cause the joints to fail (usually during the following Winter). i'm telling you from experience, it'll be the coldest day in January when it does (had to do the second one in a parking lot during a car show weekend. managed to do it in less than an hour-fun? no, but was a learning experience.

 

Awesome write up, i will probably do this on friday!! considering my temps are flying all over the place now and it scares me

 

If you have A/C make sure you remove the radio and remove the vent tube from the top of the heater core cover. Remove lower dash cover, remove radio, remove access cover in glove box. remove the heater core cover, remove two heater core straps, disconnect heater core from heater hoses, remove heater core, installation is the reverse. It is a little difficult getting the heater core pipes throught the firewall due to the angle of the pipes and the opening and how the heater core has to sit in the housing.

 

Ok, good to know. thanks for everyones help. Im about to run to autozone or napa and order the heater core from them now. Hopefully it will be in tomorrow

also would anyone know the part number if they give me a hard time. Some of the people in these stores are no brighter than a german shephard

 

You can find the part number on the website of which ever store you are going to purchase it from. NAPA & Autozone both have fairly comprehensive websites.

 

You do not need to drain all of your coolant. You do not have to pull the dash back (It may make getting the heater core through the firewall a little easier) I have changed mine twice in the life of the vehical and it is a pain getting the heater core in position. I If you are not going to slide the dash back you probally do not need to remove the computer or light. You do have to remove the kick panel for the lower dash cover to come out. In order to remove the kick panel the sill plate has to be removed. The ashtray and trim for the radio has to be removed. The radio can be pulled out and set aside if you do not want to remove completely.